Understanding the etiopathogenesis of lumbar intervertebral disc herniation: From clinical evidence to basic scientific research.

Lumbar intervertebral disc herniation, as a leading cause of low back pain, productivity loss, and disability, is a common musculoskeletal disorder that results in significant socioeconomic burdens. Despite extensive clinical and basic scientific research efforts, herniation etiopathogenesis, particularly its initiation and progression, is not well understood. Understanding herniation etiopathogenesis is essential for developing effective preventive measures and therapeutic interventions. Thus, this review seeks to provide a thorough overview of the advances in herniation-oriented research, with a discussion on ongoing challenges and potential future directions for clinical, translational, and basic scientific investigations to facilitate innovative interdisciplinary research aimed at understanding herniation etiopathogenesis. Specifically, risk factors for herniation are identified and summarized, including familial predisposition, obesity, diabetes mellitus, smoking tobacco, selected cardiovascular diseases, disc degeneration, and occupational risks. Basic scientific experimental and computational research that aims to understand the link between excessive mechanical load, catabolic tissue remodeling due to inflammation or insufficient nutrient supply, and herniation, are also reviewed. Potential future directions to address the current challenges in herniation-oriented research are explored by combining known progressive development in existing research techniques with ongoing technological advances. More research on the relationship between occupational risk factors and herniation, as well as the relationship between degeneration and herniation, is needed to develop preventive measures for working-age individuals. Notably, researchers should explore using or modifying existing degeneration animal models to study herniation etiopathogenesis, as such models may allow for a better understanding of how to prevent mild-to-moderately degenerated discs from herniating

The "Rail Technique" for Correction of Cervicothoracic Kyphosis: Case Report and Surgical Technique Description.

Cervicothoracic deformity correction often necessitates a shortening operation, consisting of a 3-column osteotomy (3CO). While effective, segmental compression and in situ and cantilever bending often place screws under considerable stress and may jeopardize deformity correction. In this report, we present the surgical technique of a novel method, the "rail technique," to shorten across a vertebral column resection (VCR) for cervicothoracic deformity correction. A 65-year-old woman with a history of a C5-pelvis posterior instrumented fusion (PSIF) presented with chin-on-chest deformity after a prior proximal junctional failure/kyphosis at T4 (30° T3-5) above a prior T5-pelvis PSIF that was stabilized in situ. She underwent an uncomplicated revision C2-T10 PSIF with shortening across a T4 VCR using the "rail technique." Postoperatively, radiographs demonstrated excellent restoration of and normalization of cervical sagittal alignment, thoracic kyphosis, focal T3-5 kyphosis (7°), and global sagittal alignment. At 1-year postoperation, she was without neck pain and reported significant improvements in self-image, mental health, satisfaction, and subscale Scoliosis Research Society-22 scores compared to preoperative values. The "rail technique" is a safe and effective method for shortening over a 3CO to correct the cervicothoracic deformity

The "Rail Technique" for Correction of Cervicothoracic Kyphosis: Case Report and Surgical Technique Description.

Cervicothoracic deformity correction often necessitates a shortening operation, consisting of a 3-column osteotomy (3CO). While effective, segmental compression and in situ and cantilever bending often place screws under considerable stress and may jeopardize deformity correction. In this report, we present the surgical technique of a novel method, the "rail technique," to shorten across a vertebral column resection (VCR) for cervicothoracic deformity correction. A 65-year-old woman with a history of a C5-pelvis posterior instrumented fusion (PSIF) presented with chin-on-chest deformity after a prior proximal junctional failure/kyphosis at T4 (30° T3-5) above a prior T5-pelvis PSIF that was stabilized in situ. She underwent an uncomplicated revision C2-T10 PSIF with shortening across a T4 VCR using the "rail technique." Postoperatively, radiographs demonstrated excellent restoration of and normalization of cervical sagittal alignment, thoracic kyphosis, focal T3-5 kyphosis (7°), and global sagittal alignment. At 1-year postoperation, she was without neck pain and reported significant improvements in self-image, mental health, satisfaction, and subscale Scoliosis Research Society-22 scores compared to preoperative values. The "rail technique" is a safe and effective method for shortening over a 3CO to correct the cervicothoracic deformity

Does number of rods matter? 4-, 5-, and 6-rods across a lumbar pedicle subtraction osteotomy: a finite element analysis

PurposeTo assess biomechanics of a lumbar PSO stabilized with different multi-rod constructs (4-, 5-, 6-rods) using satellite and accessory rods.MethodsA validated spinopelvic finite element model with a L3 PSO was used to evaluate the following constructs: 2 primary rods T10-pelvis ("Control"), two satellite rods (4-rod), two satellite rods + one accessory rod (5-rod), or two satellite rods + two accessory rods (6-rod). Data recorded included: ROM T10-S1 and L2-L4, von Mises stresses on primary, satellite, and accessory rods, factor of safety yield stress, and force across the PSO surfaces. Percent differences relative to Control were calculated.ResultsCompared to Control, 4-rods increased PSO flexion and extension. Lower PSO ROMs were observed for 5- and 6-rods compared to 4-rods. However, 4-rod (348.6 N) and 5-rod (343.2 N) showed higher PSO forces than 2-rods (336 N) and 6-rods had lower PSO forces (324.2 N). 5- and 6-rods led to the lowest rod von Mises stresses across the PSO. 6-rod had the maximum factor of safety on the primary rods.ConclusionsIn this finite element analysis, 4-rods reduced stresses on primary rods across a lumbar PSO. Although increased rigidity afforded by 5- and 6-rods decreased rod stresses, it resulted in less load transfer to the anterior vertebral column (particularly for 6-rod), which may not be favorable for the healing of the anterior column. A balance between the construct's rigidity and anterior load sharing is essential

Rates and risk factors associated with 30- and 90-day readmissions and reoperations after spinal fusions for adult lumbar degenerative pathology and spinal deformity

PURPOSE: Analyze state databases to determine variables associated with of short-term readmissions and reoperations following thoracolumbar spine fusions for degenerative pathology and spinal deformity. METHODS: Retrospective study of State Inpatient Database (2005-13, CA, NE, NY, FL, NC, UT). INCLUSION CRITERIA: age \u3e 45 years, diagnosis of degenerative spinal deformity, ≥ 3 level posterolateral lumbar spine fusion. EXCLUSION CRITERIA: revision surgery, cervical fusions, trauma, and cancer. Univariate and step-wise multivariate logistic regression analyses were performed to identify independent variables associated with of 30- and 90-day readmissions and reoperations. RESULTS: 12,641 patients were included. All-cause 30- and 90-day readmission rates were 14.6% and 21.1%, respectively. 90-day readmissions were associated with: age \u3e 80 (OR: 1.42), 8 + level fusions (OR: 1.19), hospital length of stay (LOS) \u3e 7 days (OR: 1.43), obesity (OR: 1.29), morbid obesity (OR: 1.66), academic hospital (OR: 1.13), cancer history (OR:1.21), drug abuse (OR: 1.31), increased Charlson Comorbidity index (OR: 1.12), and depression (OR: 1.20). Private insurance (OR: 0.64) and lumbar-only fusions (OR: 0.87) were not associated with 90-day readmissions. All-cause 30- and 90-day reoperation rates were 1.8% and 4.2%, respectively. Variables associated with 90-day reoperations were 8 + level fusions (OR: 1.28), LOS \u3e 7 days (OR: 1.43), drug abuse (OR: 1.68), osteoporosis (OR: 1.26), and depression (OR: 1.23). Circumferential fusion (OR: 0.58) and lumbar-only fusions (OR: 0.68) were not associated with 90-day reoperations. CONCLUSIONS: 30- and 90-day readmission and reoperation rates in thoracolumbar fusions for adult degenerative pathology and spinal deformity may have been underreported in previously published smaller studies. Identification of modifiable risk factors is important for improving quality of care through preoperative optimization

Influence of Preoperative T1-Slope and Cervical Sagittal Vertical Axis on Postoperative Cervical Sagittal Alignment Following Posterior Cervical Laminoplasty.

BackgroundAssess correlation between preoperative cervical sagittal alignment (T1 slope [T1S] and C2-C7 cervical sagittal vertical axis [cSVA]) and postoperative cervical sagittal balance after posterior cervical laminoplasty.MethodsConsecutive patients who underwent laminoplasty at a single institution with >6 weeks postoperative follow-up were divided into 4 groups based on preoperative cSVA and T1S (Group 1: cSVA <4 cm/T1S <20°; Group 2: cSVA ≥4 cm/T1S ≥20°; Group 3: cSVA <4 cm/T1S ≥20°; Group 4: cSVA <4 cm/T1S <20°). Radiographic analyses were conducted at 3 timepoints, and changes in cSVA, C2-C7 cervical lordosis (CL), and T1S -CL were compared.ResultsA total of 214 patients met inclusion criteria (28 patients had cSVA <4 cm/T1S <20° [Group 1]; 47 patients had cSVA ≥4 cm/T1S ≥20° [Group 2]; 139 patients had cSVA <4 cm/T1S ≥20° [Group 3]). No patients had cSVA ≥4 cm/T1S <20° (Group 4). Patients either had a C4-C6 (60.7%) or C3-C6 (39.3%) laminoplasty. Mean follow-up was 1.6 ± 1.32 years. For all patients, mean cSVA increased 6 mm postoperatively. cSVA significantly increased postoperatively for both groups with a preoperative cSVA <4 cm (ie, Groups 1 and 3 [P < 0.01]). For all patients, mean CL decreased 2° postoperatively. Groups 1 and 2 had significant differences in preoperative CL but nonsignificant differences at 6 weeks (P = 0.41) and last follow-up (P = 0.06).ConclusionCervical laminoplasty resulted in a mean decrease in CL. Patients with high preoperative T1S, irrespective of cSVA, were at risk of loss of CL postoperatively. While patients with low preoperative T1S and cSVA <4 cm experienced a decrease in global sagittal cervical alignment, CL was not jeopardized.Clinical relevanceThe results of this study may facilitate preoperative planning for patients undergoing posterior cervical laminoplasty.Level of evidence:

Activity and sports resumption after long segment fusions to the pelvis for adult spinal deformity: survey results of AO Spine members.

PURPOSE: To assess recommendations for when adult spinal deformity (ASD) patients may return to athletic activities after surgery. METHODS: A web-based survey was administered to members of AO Spine. The survey consisted of surgeon demographic information and questions asking when a patient undergoing a long thoracolumbar fusion (> 5 levels) with pelvic fixation for ASD would be allowed to resume unrestricted range of motion (ROM), non-contact sports, and contact sports postoperatively. Ordinal logistic regression was used to determine predictors for time to resume each activity. RESULTS: One hundred twenty four members responses were included for analysis. The majority of respondents would allow unrestricted ROM within 3 months postop (< 3 months: 81% vs > 3 months: 19%]. For when to return to non-contact sports, the most common responses were 2-3 months (26.6%), 3-4 months (26.6%), and 6-12 months (18.5%). For when to return to contact sports, the majority advised > 4 months postop [> 4 months: 4-6 months (19.2%), 6-12 months (28.0%),  > 12 months (28.8%) versus < 4 months: 1-2 months (4.0%), 2-3 months (1.6%), 3-4 months (8.8%)]. 8.8% responded they would never allow resumption of contact sports. CONCLUSION: There was significant variation between surgeons recommendations for resumption of unrestricted range of motion and sports following long fusion with pelvic fixation for ASD. An evidence-based approach to activity recommendations will require information on outcomes and complications

Lidocaine Infusion for the Management of Postoperative Pain and Delirium (LIMPP): protocol for a randomised control trial.

IntroductionPostoperative delirium is a frequent adverse event following elective non-cardiac surgery. The occurrence of delirium increases the risk of functional impairment, placement to facilities other than home after discharge, cognitive impairment at discharge, as well as in-hospital and possibly long-term mortality. Unfortunately, there is a dearth of effective strategies to minimise the risk from modifiable risk factors, including postoperative pain control and the analgesic regimen. Use of potent opioids, currently the backbone of postoperative pain control, alters cognition and has been associated with an increased risk of postoperative delirium. Literature supports the intraoperative use of lidocaine infusions to decrease postoperative opioid requirements, however, whether the use of postoperative lidocaine infusions is associated with lower opioid requirements and subsequently a reduction in postoperative delirium has not been investigated.Methods and analysisThe Lidocaine Infusion for the Management of Postoperative Pain and Delirium trial is a randomised, double-blinded study of a postoperative 48-hour infusion of lidocaine at 1.33 mg/kg/hour versus placebo in older patients undergoing major reconstructive spinal surgery at the University of California, San Francisco. Our primary outcome is incident delirium measured daily by the Confusion Assessment Method in the first three postoperative days. Secondary outcomes include delirium severity, changes in cognition, pain scores, opioid use, incidence of opioid related side effects and functional benefits including time to discharge and improved recovery from surgery. Lidocaine safety will be assessed with daily screening questionnaires and lidocaine plasma levels.Ethics and disseminationThis study protocol has been approved by the ethics board at the University of California, San Francisco. The results of this study will be published in a peer-review journal and presented at national conferences as poster or oral presentations. Participants wishing to know the results of this study will be contacted directly on data publication.Trial registration numberNCT05010148