The treatment of chronic sciatica caused by herniation of a lumbar disk has not been well studied in comparison with acute disk herniation. Data are needed on whether diskectomy or a conservative ...approach is better for sciatica that has persisted for several months.
In a single-center trial, we randomly assigned patients with sciatica that had lasted for 4 to 12 months and lumbar disk herniation at the L4-L5 or L5-S1 level in a 1:1 ratio to undergo microdiskectomy or to receive 6 months of standardized nonoperative care followed by surgery if needed. Surgery was performed by spine surgeons who used conventional microdiskectomy techniques. The primary outcome was the intensity of leg pain on a visual analogue scale (ranging from 0 to 10, with higher scores indicating more severe pain) at 6 months after enrollment. Secondary outcomes were the score on the Oswestry Disability Index, back and leg pain, and quality-of-life scores at 6 weeks, 3 months, 6 months, and 1 year.
From 2010 through 2016, a total of 790 patients were screened; of those patients, 128 were enrolled, with 64 in each group. Among the patients assigned to undergo surgery, the median time from randomization to surgery was 3.1 weeks; of the 64 patients in the nonsurgical group, 22 (34%) crossed over to undergo surgery at a median of 11 months after enrollment. At baseline, the mean score for leg-pain intensity was 7.7 in the surgical group and 8.0 in the nonsurgical group. The primary outcome of the leg-pain intensity score at 6 months was 2.8 in the surgical group and 5.2 in the nonsurgical group (adjusted mean difference, 2.4; 95% confidence interval, 1.4 to 3.4; P<0.001). Secondary outcomes including the score on the Owestry Disability Index and pain at 12 months were in the same direction as the primary outcome. Nine patients had adverse events associated with surgery, and one patient underwent repeat surgery for recurrent disk herniation.
In this single-center trial involving patients with sciatica lasting more than 4 months and caused by lumbar disk herniation, microdiskectomy was superior to nonsurgical care with respect to pain intensity at 6 months of follow-up. (Funded by Physicians' Services Incorporated Foundation; ClinicalTrials.gov number, NCT01335646.).
Abstract
Biomechanical study. To evaluate the performance of the contact surface for 3D printed patient-specific cages using CT-scan 3D endplate reconstructions in comparison to the contact surface ...of commercial cages. Previous strategies to improve the surface of contact between the device and the endplate have been employed to attenuate the risk of cage subsidence. Patient-specific cages have been used to help, but only finite-element studies have evaluated the effectiveness of this approach. There is a possible mismatch between the CT-scan endplate image used to generate the cage and the real bony endplate anatomy that could limit the performance of the cages. A cadaveric model is used to investigate the possible mismatch between 3D printed patient-specific cages and the endplate and compare them to commercially available cages (Medtronic Fuse and Capstone). Contact area and contact stress were used as outcomes. When PS cage was compared to the Capstone cage, the mean contact area obtained was 100 ± 23.6 mm
2
and 57.5 ± 13.7 mm
2
, respectively (p < 0.001). When compared to the Fuse cage, the mean contact area was 104.8 ± 39.6 mm
2
and 55.2 ± 35.1 mm
2
, respectively(p < 0.001). Patient-specific cages improve the contact area between the implant and the endplate surface, reducing the contact stress and the risk of implant subsidence during LIF surgeries.
A vertebral compression fracture (VCF) is an injury to a vertebra of the spine affecting the cortical walls and/or middle cancellous section. The most common risk factor for a VCF is osteoporosis, ...thus predisposing the elderly and postmenopausal women to this injury. Clinical consequences include loss of vertebral height, kyphotic deformity, altered stance, back pain, reduced mobility, reduced abdominal space, and reduced thoracic space, as well as early mortality. To restore vertebral mechanical stability, overall spine function, and patient quality of life, the original percutaneous surgical intervention has been vertebroplasty, whereby bone cement is injected into the affected vertebra. Because vertebroplasty cannot fully restore vertebral height, newer surgical techniques have been developed, such as kyphoplasty, stents, jacks, coils, and cubes. But, relatively few studies have experimentally assessed the biomechanical performance of these newer procedures. This article reviews over 20 years of scientific literature that has experimentally evaluated the biomechanics of percutaneous VCF repair methods. Specifically, this article describes the basic operating principles of the repair methods, the study protocols used to experimentally assess their biomechanical performance, and the actual biomechanical data measured, as well as giving a number of recommendations for future research directions.
The aim of this experimental study was to assess the biomechanical performance of a novel C1 posterior arch (C1PA) clamp compared with C1 lateral mass (C1LM) screws in constructs used to treat ...atlantoaxial instability. These constructs had either C2 pedicle (C2P) screws or C2 translaminar (C2TL) screws. Eight fresh-frozen human cadaveric ligamentous spine specimens (C0-C3) were tested under six conditions: the intact state, the destabilized state after a simulated odontoid fracture, and when instrumented with four constructs (C1LM-C2P, C1LM-C2TL, C1PA-C2P, C1PA-C2TL). Each specimen was tested in a spinal loading simulator that separately applied axial rotation, flexion-extension and lateral bending. In each test condition, displacement controlled angular motion was applied in both directions at a speed of 2 deg/s until a resulting moment of 1.5 Nm was achieved. The measured ranges of motion (ROM) of the C1-C2 segments were compared for each test condition using nonparametric Friedman tests. The destabilized state had significantly more C1-C2 motion (p < 0.05) than the intact state in all cases, and all constructs greatly reduced this motion. C2 pedicle screw constructs that used the C1PA clamp had significantly less C1-C2 motion (p < 0.05) than those with C1LM screws in flexion-extension as well as axial rotation and no statistically significant difference was detected in lateral bending. C2 translaminar screw constructs that used the C1PA clamp had significantly less C1-C2 motion (p < 0.05) than those with C1LM screws in flexion-extension and no statistically significant difference was detected in axial rotation or in lateral bending. Data from the current study suggested that constructs using the novel C1PA clamp would provide as good, or improved, biomechanical stability to the C1-C2 segment compared with constructs using C1LM screws.
Study Design
Retrospective Cohort Study
Objectives
To determine the effect of interbody cages inserted via posterior approach on segmental lordosis in the setting of preoperative lordotic vs kyphotic ...discs in patients with lumbar degenerative spondylolisthesis (LDS).
Methods
Retrospective analysis of prospectively collected data on assessment and management of LDS patients from 2 contributing centres. Patients were analyzed preoperatively and at 12-month follow-up with standing lumbar radiographs. Index level segmental lumbar lordosis (SLL), disc angle and global lumbar lordosis was measured. Patients were stratified into 4 groups based on index level disc angle and procedure: preoperative lordotic posterolateral fusion (group L-PLF); preoperative kyphotic PLF (group K-PLF); preoperative lordotic interbody fusion (IF) (group L-IF); preoperative kyphotic IF (group K-IF).
Results
A total of 100/111 (90%) patients completed follow-up with 40 in group L-IF and 48 in group K-IF. There were 18 patients in group L-PLF and 5 in group K-PLF. Among patients with preoperatively lordotic disc angles who had a worsening of SLL, group L-IF had worse SLL than group L-PLF patients, with differences persisting at one-year (mean difference 2.30, 95% CI, .3, 4.3, P = .029). Patients in group K-IF achieved improvement in SLL at one-year more frequently than group L-IF (67% vs 44%, P = .046), with similar mean improvement magnitude between groups L-IF and K-IF (−1.1, 95% CI, −3.7, 1.6, P = .415).
Conclusion
Segmental lordosis worsening was greater with preoperative index lordotic disc angles when an interbody cage was used. Patients who have a kyphotic disc preoperatively gain more lordosis with interbody cage use.
Abstract
BACKGROUND
Perioperative adverse events (AEs) lead to patient disappointment and greater costs. There is a paucity of data on how AEs affect long-term outcomes.
OBJECTIVE
To examine ...perioperative AEs and their impact on outcome after lumbar spine surgery.
METHODS
A total of 3556 consecutive patients undergoing surgery for lumbar degenerative disorders enrolled in the Canadian Spine Outcomes and Research Network were analyzed. AEs were defined using the validated Spine AdVerse Events Severity system. Outcomes at 3, 12, and 24 mo postoperatively included the Owestry Disability Index (ODI), 12-Item Short-Form Health Survey (SF-12) Physical (PCS) and Mental (MCS) Component Summary scales, visual analog scale (VAS) leg and back, EuroQol-5D (EQ5D), and satisfaction.
RESULTS
AEs occurred in 767 (21.6%) patients, and 85 (2.4%) patients suffered major AEs. Patients with major AEs had worse ODI scores and did not reach minimum clinically important differences at 2 yr (no AE: 25.7 ± 19.2, major: 36.4 ± 19.1, P < .001). Major AEs were associated with worse ODI scores on multivariable linear regression (P = .011). PCS scores were lower after major AEs (43.8 ± 9.5, vs 37.7 ± 20.3, P = .002). On VAS leg and back and EQ5D, the 2-yr outcomes were significantly different between the major and no AE groups (<0.01), but these differences were small (VAS leg: 3.4 ± 3.0 vs 4.0 ± 3.3; VAS back: 3.5 ± 2.7 vs 4.5 ± 2.6; EQ5D: 0.75 ± 0.2 vs 0.64 ± 0.2). SF12 MCS scores were not different. Rates of satisfaction were lower after major AEs (no AE: 84.6%, major: 72.3%, P < .05).
CONCLUSION
Major AEs after lumbar spine surgery lead to worse functional outcomes and lower satisfaction. This highlights the need to implement strategies aimed at reducing AEs.
Graphical Abstract
Graphical Abstract
Introduction
The vertebra accessory process (or tubercle) of the lumbar spine is an understated landmark which lies caudal to the mammillary process at the base of the transverse process. To our ...knowledge, no studies compare its relation to pedicle entry point for screw placement. We proposed to evaluate whether a valid and reliable relationship exists between the accessory process and the projected pedicle axis.
Material and Methods
The distance between the tip of the accessory process and the entry point of the pedicle screw was measured for 50 pedicles. The angle between this axis and the midline was measured. Interrater reliability was assessed intraclass correlation coefficient for two raters. Statistical analysis of the results was performed using SPSS.
Results
The mean distance between the tip of accessory process and pedicle screw entry point was 6.58 mm (SD ±2.05), and the mean angle between this axis and the midline was 29.4° medial (SD ±10.08). The ICC for the two raters for the mean distance and the mean angle was 0.974 and 0.894. The calculated mean distance between the tip of the accessory process and pedicle screw entry point was 3.2 mm (SD ±1.3) and 5.7 mm (SD ±1.9) medial and cranial respectively.
Conclusions
The accessory process is a consistent and reliable landmark to guide pedicle screw entry point, and compliments other screw insertion techniques. To our knowledge, this is the first study in the published literature to assess this relationship.
Identify patient subgroups defined by trajectories of pain and disability following surgery for degenerative lumbar spinal stenosis, and investigate the construct validity of the subgroups by ...evaluating for meaningful differences in clinical outcomes.
We recruited patients with degenerative lumbar spinal stenosis from 13 surgical spine centers who were deemed to be surgical candidates. Study outcomes (leg and back pain numeric rating scales, modified Oswestry disability index) were measured before surgery, and after 3, 12, and 24 months. Group-based trajectory models were developed to identify trajectory subgroups for leg pain, back pain, and pain-related disability. We examined for differences in the proportion of patients achieving minimum clinically important change in pain and disability (30%) and clinical success (50% reduction in disability or Oswestry score ≤22) 12 months from surgery.
Data from 548 patients (meanSD age = 66.79.1 years; 46% female) were included. The models estimated 3 unique trajectories for leg pain (excellent outcome = 14.4%, good outcome = 49.5%, poor outcome = 36.1%), back pain (excellent outcome = 13.1%, good outcome = 45.0%, poor outcome = 41.9%), and disability (excellent outcome = 30.8%, fair outcome = 40.1%, poor outcome = 29.1%). The construct validity of the trajectory subgroups was confirmed by between-trajectory group differences in the proportion of patients meeting thresholds for minimum clinically important change and clinical success after 12 postoperative months (p < .001).
Subgroups of patients with degenerative lumbar spinal stenosis can be identified by their trajectories of pain and disability following surgery. Although most patients experienced important reductions in pain and disability, 29% to 42% of patients were classified as members of an outcome trajectory subgroup that experienced little to no benefit from surgery. These findings may inform appropriate expectation setting for patients and clinicians and highlight the need for better methods of treatment selection for patients with degenerative lumbar spinal stenosis.
Study Design
Biomechanical study.
Objectives
Several strategies to improve the surface of contact between an interbody device and the endplate have been employed to attenuate the risk of cage ...subsidence. 3D-printed patient-specific cages have been presented as a promising alternative to help mitigate that risk, but there is a lack of biomechanical evidence supporting their use. We aim to evaluate the biomechanical performance of 3D printed patient-specific lumbar interbody fusion cages in relation to commercial cages in preventing subsidence.
Methods
A cadaveric model is used to investigate the possible advantage of 3D printed patient-specific cages matching the endplate contour using CT-scan imaging in preventing subsidence in relation to commercially available cages (Medtronic Fuse and Capstone). Peak failure force and stiffness were analyzed outcomes for both comparison groups.
Results
PS cages resulted in significantly higher construct stiffness when compared to both commercial cages tested (>59%). PS cage peak failure force was 64% higher when compared to Fuse cage (P < .001) and 18% higher when compared to Capstone cage (P = .086).
Conclusions
Patient-specific cages required higher compression forces to produce failure and increased the cage-endplate construct' stiffness, decreasing subsidence risk.
Degenerative cervical myelopathy is a spinal disorder resulting in progressive cord compression and neurological deficits that are assessed using the modified Japanese Orthopedic Association (mJOA) ...questionnaire. It is difficult to predict which patients will recover neurological function after surgery, making it challenging for clinicians to set postoperative patient expectations. In this study, we used mJOA subscores to identify patterns of recovery and recovery timelines in patients with moderate and severe myelopathy.
Fifty-three myelopathy patients were enrolled and completed the mJOA questionnaire both pre-surgery, and six weeks and six months post-surgery. Pearson chi-square tests were performed to assess relationships of both recovery patterns and recovery timelines with severity of disease.
Moderate myelopathy patients were significantly more likely than severe myelopathy patients to experience full recovery of upper extremity, lower extremity, and sensory domains. Disease severity did not significantly impact the timeline during which recovery occurs. Overall, >90% of patients experienced at least partial recovery by six months post surgery, 80% of which demonstrated it within the first six weeks.
This study shows the more severe the disease experienced by myelopathy patients, the more likely they will be left with permanent disabilities despite surgery. Early identification and treatment are therefore necessary to prevent worsening quality of life and increased costs of functional dependence. The recovery timelines for each subscore are similar and provide new values to guide patient expectations in their potential post-operative recovery. The overall recovery timeline is more generalizable though potentially lacking the specificity patients seek.
PDF
