Lumbar Spinal Fusion Affects Sitting Disability on the Floor.

BACKGROUND: Lumbar spinal fusion is a standard of care for certain lumbar spinal diseases. However, its impact on sitting, especially on the floor, has not been assessed, even in the countries where people usually sit on the floor instead of using a chair. METHODS: A total of 100 Korean patients who underwent lumbar spinal fusion and 47 patients who underwent decompression surgery were enrolled. In a postoperative Oswestry Disability Index (ODI) questionnaire, an additional section 11 (Sitting on the Floor) was inserted, in which the phrase "sitting in a chair" of section 5 was replaced with "sitting on the floor." The ODI scores were calculated twice using either the section with "sitting in a chair" or the section with "sitting on the floor" and comparing the two. RESULTS: In the fusion group, the mean postoperative ODI calculated with "sitting on the floor" is significantly worse than that with "sitting in a chair" (P < .0001). This difference was the same regardless of whether the fusion was done at a single level (P < .0001) or 2 or more levels (P = .006) or whether location was at L4-L5 (P = .002) or L5-S1 (P = .02) in a single-level fusion. The scores of the decompression group showed no difference. Though preoperative and postoperative ODI showed no difference between groups, the postoperative ODI using "sitting on the floor" was significantly worse in the fusion group than the decompression group (P = .009). CONCLUSION: ODI scores using "sitting on the floor" after lumbar fusion were significantly worse than those with "sitting in a chair." A sitting disability on the floor after lumbar arthrodesis has not been appreciated adequately so far and should be seriously considered if a lumbar arthrodesis is planned in a society where people's usual style of sitting is on the floor.

Comparison of cervical kinematics between patients with cervical artificial disc replacement and anterior cervical discectomy and fusion for cervical disc herniation.

BACKGROUND CONTEXT: Although anterior cervical discectomy and fusion (ACDF) is an effective treatment option for patients with cervical disc herniation, it limits cervical range of motion, which sometimes causes discomfort and leads to biomechanical stress at neighboring segments. In contrast, cervical artificial disc replacement (ADR) is supposed to preserve normal cervical range of motion than ACDF. A biomechanical measurement is necessary to identify the advantages and clinical implications of ADR. However, literature is scarce about this topic and in those available studies, authors used the static radiological method, which cannot identify three-dimensional motion and coupled movement during motion of one axis. PURPOSE: The purpose of this study was to compare the clinical parameters and cervical motion by three-dimensional motion analysis between ACDF and ADR and to investigate the ability of ADR to maintain cervical kinematics. STUDY DESIGN: This was a prospective case control study. PATIENT SAMPLE: Patients who underwent ADR or ACDF for the treatment of single-level cervical disc herniation. OUTCOME MEASURES: Visual analog scale (VAS), Korean version of Neck Disability Index (NDI, %), and three-dimensional motion analysis were used. METHODS: The patients were evaluated by VAS and the Korean version of the NDI (%) to assess pain degree and functional status. Cervical motions were assessed by three-dimensional motion analysis in terms of sagittal, coronal, and horizontal planes. Markers of 2.5 cm in diameter were attached at frontal polar (Fpz), center (Cz), and occipital (Oz) of 10-20 system of electroencephalography, C7 spinous process, and both acromions. These evaluations were performed preoperatively and 1 month and 6 months after surgery. RESULTS: The ACDF and ADR groups revealed no significant difference in VAS, NDI (%), and cervical range of motion preoperatively. After surgery, both groups showed no significant difference in VAS and NDI (%). In motion analysis, significantly more range of motion was retained in flexion and extension in the ADR group than the ACDF group at 1 month and 6 months. There was no significant difference in lateral tilt and rotation angle. In terms of coupled motion, ADR group exhibited significantly more preserved sagittal plane motion during right and left rotation and also showed significantly more preserved right lateral bending angle during right rotation than ACDF group at 1 month and 6 months. There was no significant difference in other coupled motions. CONCLUSION: Three-dimensional motion analysis could provide useful information in an objective and quantitative way about cervical motion after surgery. In addition, it allowed us to measure not only main motion but also coupled motion in three planes. ADR demonstrated better retained cervical motion mainly in sagittal plane (flexion and extension) and better preserved coupled sagittal and coronal motion during transverse plane motion than ACDF. ADR had the advantage in that it had the ability to preserve more cervical motions after surgery than ACDF.

Clinical and radiological comparison of femur and fibular allografts for the treatment of cervical degenerative disc diseases.

OBJECTIVE: This consecutive retrospective study was designed to analyze and to compare the efficacy and outcomes of anterior cervical discectomy and fusion (ACDF) using a fibular and femur allograft with anterior cervical plating. METHODS: A total of 88 consecutive patients suffering from cervical degenerative disc disease (DDD) who were treated with ACDF from September 2007 to August 2010 were enrolled in this study. Thirty-seven patients (58 segments) underwent anterior interbody fusion with a femur allograft, and 51 patients (64 segments) were treated with a fibular allograft. The mean follow-up period was 16.0 (range, 12-25) months in the femur group and 19.5 (range, 14-39) months in the fibular group. Cage fracture and breakage, subsidence rate, fusion rate, segmental angle and height and disc height were assessed by using radiography. Clinical outcomes were assessed using a visual analog scale and neck disability index. RESULTS: At 12 months postoperatively, cage fracture and breakage had occurred in 3.4% (2/58) and 7.4% (4/58) of the patients in the femur group, respectively, and 21.9% (14/64) and 31.3% (20/64) of the patients in the fibular group, respectively (p<0.05). Subsidence was noted in 43.1% (25/58) of the femur group and in 50.5% (32/64) of the fibular group. No difference in improvements in the clinical outcome between the two groups was observed. CONCLUSION: The femur allograft showed good results in subsidence and radiologic parameters, and sustained the original cage shape more effectively than the fibular allograft. The present study suggests that the femur allograft may be a good choice as a fusion substitute for the treatment of cervical DDD.

Factors affecting clinical outcomes in treating patients with grade 1 degenerative spondylolisthesis using interspinous soft stabilization with a tension band system: a minimum 5-year follow-up.

STUDY DESIGN: Retrospective clinical study. OBJECTIVE: To explore the factors influencing the clinical outcomes and motion-preserving stabilization after interspinous soft stabilization (ISS) with a tension band system for grade 1 degenerative spondylolisthesis (DS). SUMMARY OF BACKGROUND DATA: Despite increasing recognition of the benefits of dynamic stabilization systems for treating lumbar degenerative disorders, the factors affecting the clinical and radiological outcomes of these systems have rarely been identified. METHODS: Sixty-five patients (mean age, 60.3 years) who underwent ISS with a tension band system between 2002 and 2004 were analyzed. The mean follow-up period was 72.5 months. The patients were divided according to the postsurgical clinical improvements into the optimal (n = 44) and suboptimal groups (n = 21), and the radiological intergroup differences were analyzed. Multiple linear regression analysis was performed to determine the impact of the radiological factors on the clinical outcomes. RESULTS: Significant intergroup differences were observed on the follow-up clinical examination. Radiologically, total lumbar lordosis (TLL) and segmental lumbar lordosis (SLL) were significantly improved only in the optimal group, resulting in significant intergroup differences in TLL (P = 0.023), SLL (P = 0.001), and the L1 tilt (P = 0.002). All these measures were closely associated with postoperative segmental lumbar lordosis, which also was the most influential radiological variable for the clinical parameters. CONCLUSION: In the patients with grade 1 DS, the back pain relief and functional improvement following ISS were affected by the improvements in the sagittal spinal alignment through the achievement of segmental lumbar lordosis. ISS can be an alternative treatment to fusion surgery for grade 1 DS in patients who do not require fixation or reduction.

Comparison of multilevel oblique corpectomy with and without image guided navigation for multi-segmental cervical spondylotic myelopathy.

OBJECTIVE: Multilevel Oblique Corpectomy (MOC) is an emerging technique for surgical treatment of multi-segmental cervical spondylotic myelopathy (CSM) featuring extensive ossification of the posterior longitudinal ligament (OPLL). However, the use of an oblique drilling plane is unfamiliar to most surgeons and there is no anatomical landmark present on the posterior portion of the vertebral body. To overcome these difficulties, the authors used intraoperative C-arm-based image guided navigation (IGN), and this study was conducted to evaluate the efficacy of IGN in MOC. METHODS: Following the introduction of IGN for MOC, 24 patients underwent MOC procedures at our institution. Two patients who had undergone previous cervical operations were excluded from the present study. Of the remaining 22 patients, 11 underwent MOC with IGN, and 11 underwent MOC without IGN support. The completeness of MOC (CMOC) is measured as the sum of the bilateral remaining posterior body minus the remaining approach-side anterior body in millimeters at the most compressive level. For each patient, the preoperative Japanese Orthopaedic Association Score (JOAS) and postoperative 5th day JOAS were collected as well as several other perioperative parameters. RESULTS: The mean CMOC was 0.89 mm for the IGN group and 5.9 mm for the control group. The mean change in JOAS was 5.58 for the IGN group and 3.34 for the control group at 1-year follow-up. In the control group, two patients underwent re-exploration due to remaining OPLL. Despite the intraoperative IGN set-up time, the mean operation time for the IGN group was shorter than that for the control group (248 min versus 259 min). Mean treated levels were 3.55 for the IGN group and 3.36 for the control group. CONCLUSION: Through the use of image guided navigation, it was possible to accomplish faster and more complete MOC.

Anterior bone cement augmentation in anterior lumbar interbody fusion and percutaneous pedicle screw fixation in patients with osteoporosis.

OBJECT: The purpose of the present study was to evaluate the efficacy of anterior polymethylmethacrylate (PMMA) cement augmentation in instrumented anterior lumbar interbody fusion (ALIF) for patients with osteoporosis. METHODS: Sixty-two patients with osteoporosis who had undergone single-level instrumented ALIF for spondylolisthesis and were followed for more than 2 years were included in the study. The patients were divided into 2 groups: instrumented ALIF alone (Group I) and instrumented ALIF with anterior PMMA augmentation (Group II). Sixty-one patients were interviewed to evaluate the clinical results, and plain radiographs and 3D CT scans were obtained at the last follow-up in 46 patients. RESULTS: The mean degree of cage subsidence was significantly higher in Group I (19.6%) than in Group II (5.2%) (p = 0.001). The mean decrease of vertebral body height at the index level was also significantly higher in Group I (10.7%) than in Group II (3.9%) (p = 0.001). No significant intergroup differences were observed in the incidence of radiographic adjacent-segment degeneration (ASD) or in terms of pain and functional improvement. The incidences of clinical ASD (23% in Group I and 10% in Group II) were not significantly different. There was 1 case of nonunion and 3 cases of screw migration in Group I, but none resulted in implant failure. CONCLUSIONS: Anterior PMMA augmentation during instrumented ALIF in patients with osteoporosis was useful to prevent cage subsidence and vertebral body collapse. In addition, PMMA augmentation did not increase the nonunion rate and incidence of ASD.

Adjacent segment disease after interbody fusion and pedicle screw fixations for isolated L4-L5 spondylolisthesis: a minimum five-year follow-up.

STUDY DESIGN: A retrospective study. OBJECTIVE: The purpose of this study are (1) to analyze prevalence of clinical and radiologic adjacent segment diseases (ASD), (2) to find precipitating factor of clinical ASD in each isthmic and degenerative spondylolisthesis groups, and (3) to compare clinical and radiologic change in isthmic and degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: There is no clinical report regarding the use of magnetic resonance imaging (MRI) for evaluating ASD in patient who underwent 360° fusion with single-level spondylolisthesis with healthy adjacent segment. METHODS: A total of 69 patients who underwent instrumented single-level interbody fusion at the L4-L5 level and showed no definitive degenerated disc in adjacent segments on preoperative MRI and plain radiographs were evaluated at more than 5 years after surgery. The patients were divided into 2 groups: group I was isthmic spondylolisthesis patients and group II was degenerative spondylolisthesis patients. The radiologic ASD was diagnosed by plain radiographs and MRI. Clinical ASD is defined as symptomatic spinal stenosis, intractable back pain, and subsequent sagittal or coronal imbalance with accompanying radiographic changes. Symptomatic spinal stenosis was defined as stenosis diagnosed by MRI and combined with neurologic claudication. RESULTS: The prevalence of radiologic ASD on group I and group II was 72.7% and 84.0%, respectively. About 7 (15.9%) patients showed clinical ASD in group I and 6 (24.0%) patients showed clinical ASD in group II. MRI showed significant reliability for diagnosis of clinical ASD. Compared with patients with asymptomatic ASD, patients with clinical ASD showed significantly less postoperative lordotic angle at the L4-L5 level (i.e., less than 20°) in both groups. CONCLUSION: Maintaining postoperative L4-L5 segmental lordotic angle at about 20° or more is important for prevention of clinical ASD in single-level 360° fusion operation. MRI is reliable method for diagnosing clinical ASD.

Transcorporeal approach for disc herniation at the C2-C3 level: a technical case report.

The authors describe a less invasive approach for a disc herniation at the high cervical region. A 68-year-old female patient presented with posterior neck and shoulder pain, and tingling sensation and numbness in the left hand after she fell down stairs 2 months before presentation. On neurologic examination, the power of flexion and extension of the left elbow and grasping of the left hand was decreased. Hoffmann sign was positive in both hands. Magnetic resonance imaging showed a huge herniation of the C2-C3 disc compressing the left paramedian area of the spinal cord. After a routine surgical exposure for discectomy of the C3-C4 disc, a drill hole of about 5 mm diameter was made at the middle of the C3 vertebral body. The hole was extended cranioposteriorly to the superoposterior border of the C3 endplate. The posterior disc at the midline of the C2-C3 was removed first then the herniated disc completely removed. Postoperatively, the patient showed improvement of the neck and shoulder pain and numbness of the hand. At 7-month follow-up, she completely recovered from her neurologic symptoms. Compared with the other approaches to high cervical lesion, the current approach was straightforward and less invasive. If there is no need to stabilize the spinal motion segment, this transcorporeal approach can be a useful surgical option as it decreases the extent of tissue dissection of the submandibular retropharyngeal area that might increase the risk of neurovascular injury.

Comparison of percutaneous endoscopic lumbar discectomy and open lumbar microdiscectomy for recurrent disc herniation.

OBJECTIVE: The purpose of this study was to compare clinical and radiological outcomes of percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy (OLM) for recurrent disc herniation. METHODS: Fifty-four patients, who underwent surgery, either PELD (25 patients) or repeated OLM (29 patients), due to recurrent disc herniation at L4-5 level, were divided into two groups according to the surgical methods. Excluded were patients with sequestrated disc, calcified disc, severe neurological deficit, or instability. Clinical outcomes were assessed using Visual Analogue Scale (VAS) score and Oswestry Disability Index (ODI). Radiological variables were assessed using plain radiography and/or magnetic resonance imaging. RESULTS: Mean operating time and hospital stay were significantly shorter in PELD group (45.8 minutes and 0.9 day, respectively) than OLM group (73.8 minutes and 3.8 days, respectively) (p < 0.001). Complications occurred in 4% in PELD group and 10.3% in OLM group in the perioperative period. At a mean follow-up duration of 34.2 months, the mean improvements of back pain, leg pain, and functional improvement were 4.0, 5.5, and 40.9% for PELD group and 2.3, 5.1, and 45.0% for OLM group, respectively. Second recurrence occurred in 4% after PELD and 10.3% after OLM. Disc height did not change after PELD, but significantly decreased after OLM (p = 0.0001). Neither sagittal rotation angle nor volume of multifidus muscle changed significantly in both groups. CONCLUSION: Both PELD and repeated OLM showed favorable outcomes for recurrent disc herniation, but PELD had advantages in terms of shorter operating time, hospital stay, and disc height preservation.

Biomechanical evaluation of an interspinous stabilizing device, Locker.

STUDY DESIGN: A biomechanical study. OBJECTIVE: To evaluate the biomechanical properties of a novel dynamic interspinous device named Locke SUMMARY OF BACKGROUND DATA: There has been no biomechanical study on this device. METHODS: Five human cadaveric lumbar spine specimens (L2-S1) were tested in the following sequence: (1) intact state; (2) after removal of the interspinous ligaments of L3-L4; (3) after application of the Locker at the interspinous space; (4) after destabilization of the L3-L4 motion segments; and (5) after reapplication of the Locker to the destabilized segments. Range of motion (ROM) and intradiscal pressure were measured by a video-based motion capture system and needle transducers. RESULTS: Applied to the intact spine, the Locker significantly reduced the ROM of the segment in extension and flexion without significant effect on lateral bending and/or axial rotation. When applied to the destabilized segment, it significantly reduced the ROM in all directions of movement except in axial rotation, where it failed to restore the ROM of the segment. The ROM of adjacent segments was not significantly affected by the application of the Locker. Pressures at the posterior anulus and central nucleus were decreased by application of the Locker. CONCLUSION: The Locker showed a significant stabilizing effect on the spinal motion segment both in the intact and destabilized spine without any significant effect on adjacent segments. It also decreased the pressures of the posterior anulus and central nucleus significantly. However, in the destabilized spine, it showed no stabilizing effect in axial rotation. This biomechanical property should be considered in clinical application.

Percutaneous endoscopic approach for highly migrated intracanal disc herniations by foraminoplastic technique using rigid working channel endoscope.

STUDY DESIGN: A retrospective analysis of 59 patients operated for excision of soft highly migrated intracanal lumbar disc herniations by percutaneous endoscopic foraminoplasty. OBJECTIVE: To describe a safe and effective percutaneous endoscopic technique for removal of migrated herniations and report the results on the basis of modified MacNab criteria. SUMMARY OF BACKGROUND DATA: Migrated herniations pose a great challenge even for experienced endoscopic surgeons. These herniations are hidden from the endoscopic view by anatomic barriers like hypertrophied facet, inferior pedicle and foraminal ligaments rendering percutaneous endoscopic transforaminal lumbar discectomy (PELD) by conventional approach, difficult with high failure rate. Foraminoplasty, which means enlargement of foramen by undercutting ventral part of superior-facet, upper border of inferior pedicle along with ablation of foraminal ligament, can help us to address this issue. METHODS: Fifty-nine patients with soft highly migrated herniations who underwent PELD with foraminoplasty under local anesthesia from January 2002 to June 2006 were analyzed retrospectively. Patients were evaluated by postoperative Visual Analog Scale for leg pain and Oswestry Disability Index scores. Outcomes were graded according to modified MacNab criteria. RESULTS: Mean follow-up was 25.4 months. Mean visual analog scale score for radicular pain improved from 8.01 to 1.56, and mean Oswestry disability Index improved from 61.6 to 10.76. Based on modified MacNab criteria, 91.4% of patients experienced satisfactory outcome. Three patients had persistent leg pain after surgery. One patient underwent a repeat-PELD on next day and the other after 1 month. Both were relieved of symptoms. Third patient was subjected to open discectomy after 25 weeks from the first operation and showed improvement. Two patients had recurrent herniation at same level after 6 months; 1 patient underwent repeat PELD, and the other underwent open discectomy. Both patients had good results. CONCLUSION: Foraminoplastic-PELD is safe and effective procedure for surgical treatment of soft migrated herniations. The results are comparable to results of open discectomy.

The clinical characteristics and risk factors for the adjacent segment degeneration in instrumented lumbar fusion.

STUDY DESIGN: A retrospective study. OBJECTIVE: The aims of this study were to evaluate the clinical significance of, characteristics of, and risk factors for adjacent segment degeneration (ASD) in patients who have undergone instrumented lumbar fusion. SUMMARY OF BACKGROUND DATA: ASD has been considered a potential long-term complication of spinal arthrodesis. However, the exact mechanisms and risk factors related to ASD are not completely understood. METHODS: A total of 48 patients who underwent instrumented lumbar fusion at L4-5 and had minimal ASD preoperatively were evaluated. The patients were divided into 2 groups at follow-up according to the development of ASD defined by radiologic criteria. Through review of their medical records and the radiologic files, the following variables were evaluated in the 2 groups: basic demographic data, body weight, body height, body mass index, bone mineral density, types of surgical approaches, preoperative and postoperative segmental and lumbar lordosis, and clinical outcomes. RESULTS: ASD was found in 30 (62.5%) patients. The variables that showed statistical intergroup differences were the mean age at surgery, the mean difference in the degree of preoperative from postoperative lumbar lordosis, and the proportion of patients who underwent anterior lumbar interbody fusion. However, there were no statistically significant intergroup differences in the Japanese Orthopedic Association score at 1-year postoperatively or at the final follow-up, or in the recovery rate, success rate, and complication rate. CONCLUSIONS: Radiographic ASD is relatively common long-term finding associated with instrumented lumbar fusion. However, radiographic evidence of ASD does not necessarily correlate with a poor outcome. Our results suggest that advanced age, anterior lumbar interbody fusion, and the restoration of the preoperative standing lumbar lordosis may have a protective effect against the development of ASD.

Posterior avulsion fracture at adjacent vertebral body during cervical disc replacement with ProDisc-C: a case report.

STUDY DESIGN: A case report. OBJECTIVE: To report posterior avulsion fractures at the adjacent vertebral bodies that occurred during cervical arthroplasty with ProDisc-C, which was thought to be related to design of the prosthesis and lack of the prudence in surgical technique. SUMMARY OF BACKGROUND DATA: There is no previous report on the avulsion fracture of the posterior vertebral body during cervical arthroplasty. METHODS: A 32-year-old-man presented with painful numbness and weakness of the right upper extremity for 2 months. On magnetic resonance imaging and computer tomography scans, a huge disc herniation at C6-C7 segment compressing the right C7 root and the spinal cord was identified. To prevent acceleration of degeneration of the C5-C6 segment, disc replacement of the C6-C7 with the ProDisc-C after anterior discectomy was planned. RESULTS: Nearing the end of the second chiseling with a box cutting chisel, and following further mallet impaction to insert the chisel a bit more, copious bleeding occurred. Hurried hemostasis was accomplished. The posterior central vertebral bodies of C6 and C7 were found to be fractured and avulsed bony fragments were displaced posteriorly compressing the spinal cord. The bony fragments were carefully removed and the ProDisc-C was inserted as planned. The patient recovered without neurologic deficit. CONCLUSIONS: Owing to keel design of the prosthesis, the possibility of posterior avulsion fracture of the vertebral body should always be appreciated in cervical disc arthroplasty with ProDisc-C, especially during chiseling with the box cutting chisel and inserting the prosthesis. Further, insertion of either of them beyond the posterior ends of the keel cuts made by a keel cutting chisel should not be tried.

CHARITE versus ProDisc: a comparative study of a minimum 3-year follow-up.

STUDY DESIGN: A retrospective study. OBJECTIVES: To evaluate and compare clinical and radiologic outcomes of the CHARITE and ProDisc. SUMMARY OF BACKGROUND DATA: There is no clinical report comparing CHARITE and ProDisc. METHODS: Among a total of 61 patients who underwent total disc replacement, 57 patients followed more than 3 years were enrolled. The CHARITE was used in 33 patients and ProDisc in 24. MRI follow-up was possible in 52 patients. Clinical and radiologic data including range of motion (ROM) and facet degeneration of the replaced segment, and degeneration of the disc at the adjacent level were evaluated. RESULTS: Mean percentage improvement of Oswestry Disability Index (ODI) score was 78.9% in the CHARITE group and 75.8% in ProDisc group. The mean improvement of the Visual Analogue Scale (VAS) pain score was 72% in the CHARITE and 74.2% in ProDisc. There was no statistical difference between 2 groups in improvement rates either of the ODI scores and VAS scores. Degradation of the facets was seen in 36.4% of the CHARITE and 32% of the ProDisc. Degradation of disc degeneration at the adjacent level above the index level was seen in 19.4% in the CHARITE and 28.6% in the ProDisc. The degradation rates of facet joints and disc at adjacent segment between the 2 groups were not significantly different. Segmental ROM of the replaced segments was well preserved, but ROM of L5-S1 of the ProDisc was significantly less than that of the CHARITE. CONCLUSIONS: While clinical outcomes of both CHARITE and ProDisc groups were fairly good, the facet joint of the index level and the disc at the adjacent level showed an aggravation of the degenerative process in a significant number of patients, regardless of the device used, raising concerns of possible late consequences of total disc replacement, especially regarding facet arthrosis and adjacent segment disease.

Soft stabilization with an artificial intervertebral ligament in grade I degenerative spondylolisthesis: comparison with instrumented posterior lumbar interbody fusion.

BACKGROUND: The purpose of this retrospective study was to evaluate the efficacy of soft stabilization with an artificial intervertebral ligament after microdecompression for the treatment of grade I degenerative spondylolisthesis. METHODS: From a total of 54 patients with degenerative spondylolisthesis who were treated surgically from May 2000 to April 2003, 36 patients who showed grade I spondylolisthesis without evidence of concomitant disc herniation necessitating discectomy were enrolled in the study. After decompression, the patients had undergone either soft stabilization with an artificial intervertebral ligament (n = 17) or instrumented posterior lumbar interbody fusion (PLIF; n = 19). RESULTS: The average follow-up period was 24 months for the PLIF group and 16 months for the soft stabilization group. In the PLIF group, preoperative mean scores of 60% on the Oswestry Disability Index, 8.8 on the visual analog scale (VAS) for low-back pain, and 9.3 on the VAS for leg pain improved to 28%, 4.1, and 2.6, respectively, after surgery. Corresponding scores in the soft stabilization group were 55%, 8.4, and 8.9, improving to 25%, 4.1, and 2.2 after surgery. There were no significant differences between the 2 groups in any of these clinical parameters. Patients' subjective improvement rates and satisfaction with the surgical procedure were higher in the soft stabilization group, but the differences were not significant. Mean operation time and mean blood loss were significantly lower in the soft stabilization group than in the PLIF group. In the soft stabilization group, there were 3 cases of progression of slippage in patients who had had preoperative slippage of more than 20%; there was 1 dural tear in the PLIF group. CONCLUSIONS: Patients with grade I degenerative spondylolisthesis who received soft stabilization with an artificial intervertebral ligament after microdecompression had clinical outcomes similar to those of patients who received PLIF. Since soft stabilization can be done in a much less invasive way than fusion, if slippage is 20% or less, soft stabilization with an artificial ligament is a viable alternative to fusion for patients who are elderly or who have significant comorbidities that make a prolonged operation inadvisable. LEVEL OF EVIDENCE: This study was a retrospective comparative study with a very limited population (level III evidence).

Early clinical and radiologic outcomes of cervical arthroplasty with Bryan Cervical Disc prosthesis.

Among 61 patients underwent disc replacement with the Bryan prosthesis, 47 patients were followed more than 3 months and their clinical and radiologic data were retrospectively analyzed to clarify very early clinical and radiologic outcomes and complications of disc arthroplasty with the Bryan Cervical Disc prosthesis during the learning period. Mean follow-up period was 6 months. Mean age was 45.6 years. Single-level procedure was done in 39 patients and 2-level in 8; a total of 55 levels replaced. Neck disability index improved from 59.8% to 22.9%. Visual analog pain score (VAS) of the neck improved from 8.4 to 1.6. VAS of shoulder/arm pain improved from 8.8 to 2.4. Mean patients' subjective improvement rate of symptoms was 71.1%. According to improvement in the neck disability index and VAS (over 50% improvement rate in each parameter), patients' subjective improvement rate (over 50%), and patients' satisfaction, the surgical success was achieved in 39 patients (83%). Eight patients (17%) showed failure. Mean segmental angle became more kyphotic after surgery from -0.7 degree of kyphosis (-11 to 7.7 degrees) to -1.3 degrees (-32 to 20.9 degrees) without statistical significance (P=0.55). Among 24 segments that showed preoperative kyphosis, 13 (54.2%) showed aggravated kyphosis, 7 (29.1%) showed decreased kyphosis and 4 (16.7%) recovered to lordosis. Among 31 segments that showed preoperative lordosis, 19 (61.3%) showed loss of lordosis and 12 (38.7%) showed increased lordosis. Mean range of motion increased significantly after surgery (6.7 to 8.5 degrees, P=0.04). Preoperative and postoperative segmental kyphosis was not related to clinical success. Cervical arthroplasty with the Bryan Cervical Disc prosthesis failed to restore segmental lordotic angle. A concern arises because it is well known that the fusion in kyphotic curvature causes more frequent problems on adjacent levels in anterior cervical discectomy and fusion. For the present, it seems preferable to exclude the patient who already has significant segmental kyphosis from disc arthroplasty with Bryan Cervical Disc prosthesis.

Vertical split fracture of the vertebral body following total disc replacement using ProDisc: report of two cases.

As ProDisc has a tall keel on the plates, it has the potential to cause a vertical fracture of the vertebral body. However, to our knowledge, there is no previously reported case of a vertical split fracture of the vertebral body after ProDisc disc arthroplasty that was attributed to the keel design of the ProDisc. We report two cases of vertical split fracture of the vertebral body after total disc replacement (TDR) with ProDisc and discuss the issue of the height of the keel of the prosthesis. Even though there was no serious clinical consequence as a result of the fracture in our cases, except the fact that the patients were dissatisfied with the surgery at 3-month follow-up because of the prolonged back pain, the potential of the fracture to cause other serious complications such as hematoma, device migration, or surgical failure cannot be ignored. The keel design of the ProDisc has the disadvantage that it can cause a vertebral body fracture in some patients. Therefore, care should be exercised not to fracture the vertebral body when TDR is done with the ProDisc, especially in a patient with small vertebral body height or when it is done at multiple levels.

Fluoroscopically assisted percutaneous translaminar facet screw fixation following anterior lumbar interbody fusion: technical report.

STUDY DESIGN: A technical report of fluoroscopically assisted percutaneous translaminar facet screw fixation after anterior lumbar interbody fusion (ALIF). OBJECTIVES: To describe a minimally invasive translaminar facet screw fixation technique that was modified from the Magerl method, and to assess its technical feasibility and clinical efficacy. SUMMARY OF BACKGROUND DATA: There is no previous study in the literature on percutaneous translaminar facet screw fixation assisted only by fluoroscopy without using any specially designed guiding device. Also, there is no previous study involving a screw insertion technique in which the screw is directed to purchase the pedicle while traversing the lamina and transfixing the facet joint. METHODS: A total of 20 patients with degenerative spinal disease underwent ALIF and supplementary percutaneous translaminar facet screw fixation under fluoroscopic guidance from 2001 through 2002. Their clinical and radiologic data were collected and analyzed. RESULTS: A total of 65 screws were inserted. Seven screws (10.8%) were found to have violated laminae walls but none injured or compressed neural structures directly. The purchases of the facet joints were all successful, but insertion into the pedicle in perfect position was successful in 55 screws (84.6%). Radiologic fusion occurred in all fused levels (100%). Estimated blood loss was 222.5 mL (100-520), and no blood transfusions were needed in any of the cases. There was only one complication related to facet screw fixation, in which the distal tip of a superior articular process was fractured caused by repeated drilling with a K-wire. CONCLUSIONS: Percutaneous translaminar facet screw fixation using fluoroscopy is technically feasible. It seems that the fluoroscopically assisted percutaneous translaminar facet pedicle screw fixation is a useful, minimally invasive posterior augmenting method following ALIF.

Partial disc replacement with the PDN prosthetic disc nucleus device: early clinical results.

The aim of this study was to evaluate the efficacy of the PDN prosthetic disc nucleus device for the treatment of chronic discogenic back pain caused by degenerative disc disease. Among the 48 patients who underwent nucleus replacement surgery from January 2001 through May 2002, 46 patients were followed >6 months. The mean Oswestry Disability Index score was 58.9% preoperatively, and it improved to 18% at the 1-year follow-up. Visual Analogue Pain Scale scores improved from a preoperative mean of 8.5 to 3.1 after 1 year. The mean Prolo Scale score also improved from 5.2 preoperatively to 7.2 at 1 year. Major complications included four cases of device migration, requiring revision surgery, and infection in one patient. According to MacNab's criteria, results were excellent in 5 patients (10.9%), good in 31 (67.4%), fair in 3 (6.5%), and poor in 7 (15.1%). The overall clinical success rate was 78.3%. Nucleus replacement with the PDN device seemed to be effective in treating patients with chronic discogenic back pain caused by degenerative disc disease.