What is the early fate of adjacent segmental lordosis compensation at L3-4 and L5-S1 following a lateral versus transforaminal lumbar Interbody Fusion at L4-5?

INTRODUCTION: Degenerative spondylolisthesis causes translational and angular malalignment, resulting in a loss of segmental lordosis. This leads to compensatory adjustments in adjacent levels to maintain balance. Lateral lumbar interbody fusion (LLIF) and transforaminal lumbar interbody fusion (TLIF) are common techniques at L4-5. This study compares compensatory changes at adjacent L3-4 and L5-S1 levels six months post LLIF versus TLIF for grade 1 degenerative spondylolisthesis at L4-5. METHODS: A retrospective study included patients undergoing L4-5 LLIF or TLIF with posterior pedicle screw instrumentation (no posterior osteotomy) for grade 1 spondylolisthesis. Pre-op and 6-month post-op radiographs measured segmental lordosis (L3-L4, L4-L5, L5-S1), lumbar lordosis (LL), and pelvic incidence (PI), along with PI-LL mismatch. Multiple regressions were used for hypothesis testing. RESULTS: 113 patients (61 LLIF, 52 TLIF) were studied. TLIF showed less change in L4-5 lordosis (mean = 1.04°, SD = 4.34) compared to LLIF (mean = 4.99°, SD = 5.53) (p = 0.003). L4-5 angle changes didn't correlate with L3-4 changes, and no disparity between LLIF and TLIF was found (all p > 0.16). In LLIF, greater L4-5 lordosis change predicted reduced compensatory L5-S1 lordosis (p = 0.04), while no significant relationship was observed in TLIF patients (p = 0.12). CONCLUSION: LLIF at L4-5 increases lordosis at the operated level, with compensatory decrease at L5-S1 but not L3-4. This reciprocal loss at adjacent L5-S1 may explain inconsistent improvement in lumbar lordosis (PI-LL) post L4-5 fusion.

Trans-sacral interbody fixation in long fusions to the sacrum for adult spinal deformity: complications and fusion rates at minimum two years follow-up.

PURPOSE: This study aims to investigate the fusion rate and complications associated with trans-sacral interbody fusion (TSIF) in long fusions to the sacrum for adult spinal deformity (ASD) over a two year follow-up period. Potential predictor variables associated with pseudarthrosis were also examined. METHODS: A retrospective clinical review was conducted on a consecutive series of ASD patients who underwent long fusions to the sacrum, with TSIF performed as a same-day or staged procedure. Patient demographics, bone mineral density, operative details, perioperative and late complications, and fusion rates were reviewed. Univariate analysis was used to identify the risk factors associated with pseudarthrosis. RESULTS: The study included 43 patients with an average age of 55.3 ± 8.9 years. The perioperative complication rate was 28%, with 12% of the complications directly related to TSIF. The late complication rate was 33%, with 16% related to TSIF. The most common complications were pseudarthrosis (14%) and postoperative ileus (7%). The overall radiographic fusion rate at two years was 86%. Univariate analysis revealed that revision surgery was significantly associated with pseudarthrosis (p = 0.027). Over the follow-up period, patients who underwent TSIF during long posterior fusions to the sacrum showed improvement in overall SRS scores, ODI scores, and SF-36 physical health and mental health (p < 0.05). CONCLUSION: TSIF is a relatively safe and minimally invasive method for achieving interbody fusion at the lumbosacral junction in the treatment of ASD, with acceptable fusion rates and a low complication rate. However, TSIF is not recommended for revision reconstruction in ASD.

Lumbar computed tomography scans are not appropriate surrogates for bone mineral density scans in primary adult spinal deformity.

OBJECTIVE The authors examined the correlation between lumbar spine CT Hounsfield unit (HU) measurements and bone mineral density measurements in an adult spinal deformity (ASD) population. METHODS Patients with ASD were identified in the records of a single institution. Lumbar CT scans were reviewed, and the mean HU measurements from L1-4 were recorded. Bone mineral density (BMD) was assessed using femoral neck and lumbar spine dual-energy x-ray absorptiometry (DEXA). The number of patients who met criteria for osteoporosis was determined for each imaging modality. RESULTS Forty-eight patients underwent both preoperative DEXA and CT scanning. Forty-three patients were female and 5 were male. Forty-seven patients were Caucasian and one was African American. The mean age of the patients was 62.1 years. Femoral neck DEXA was more likely to identify osteopenia (n = 26) than lumbar spine DEXA (n = 8) or lumbar CT HU measurements (n = 6) (p < 0.001). There was a low-moderate correlation between lumbar spine CT and lumbar spine DEXA (r = 0.463, p < 0.001), and there was poor correlation between lumbar spine CT and femoral neck DEXA (r = 0.303, p = 0.036). CONCLUSIONS Despite the opportunistic utility of lumbar spine CT HU measurements in identifying osteoporosis in patients undergoing single-level fusion, these measurements were not useful in this cohort of ASD patients. The correlation between femoral neck DEXA and HU measurements was poor. DEXA assessment of BMD in ASD patients is essential to optimize the care of these complicated cases.

Adolescent Idiopathic Scoliosis: Update on Bracing, Surgical Techniques, and Patient Safety.

The primary goal in the management of adolescent idiopathic scoliosis is to prevent the progression of spinal deformity either with the use of a brace or with surgery. The goals of surgery, if indicated, are to correct the spinal deformity safely and to preserve overall spinal balance and as many motion segments as possible, which maximizes the long-term health of a patient's spine. Recently, tremendous advances have been made in the surgical techniques that are used to correct adolescent idiopathic scoliosis, and improved tools have allowed surgeons to perform spinal deformity surgery as safely and with as few complications as possible. Surgeons should be aware of recent evidence that demonstrates the efficacy of bracing in patients who have adolescent idiopathic scoliosis. In addition, surgeons should understand recent advances in spinal deformity surgery with regard to fusion level selection, implant placement, three-dimensional deformity correction, and techniques that are used to minimize perioperative complications.

Cervical spine disease in rheumatoid arthritis: incidence, manifestations, and therapy.

Cervical spine involvement in patients with rheumatoid arthritis (RA) and other inflammatory arthropathies is common. While the radiographic features can be dramatic in untreated disease, patients may remain asymptomatic making treatment decisions challenging. Further, subtle clinical presentations can belie serious myelopathy because peripheral joint involvement can make interpreting the physical exam difficult. While new pharmacologic therapies have drastically reduced the morbidity of the widespread joint destruction that occurs in RA, patients remain at risk for symptomatic occipitocervical, atlantoaxial, or subaxial instability causing myelopathy, deformity, and premature death. In this review, we discuss the clinical presentation of RA patients with cervical spine disease as well as the indications and outcomes of surgical treatment.

Cervical osteotomies for neurological deformities.

PURPOSE: To report our experience and technique for performing cervical osteotomies under the setting of cervical deformity and myelopathy. METHODS: Patients who underwent cervical osteotomies for CD with myelopathy were identified in a 10 year period from 2000 to 2010. Demographics, surgery type, osteotomy type, operative details, and radiographs were collected for pre-operative and ultimate post-operative time points. Cervical lordosis (CL) and basion plumb line were collected to assess angular and translational corrections. RESULTS: In the study period, a total of 35 patients underwent a cervical osteotomy for fixed cervical deformity with a diagnosis of cervical myelopathy or myeloradiculopathy with an average follow-up of 3.4 years (range 1.0-6.3). The cohort was separated into two groups based on the type of surgical approach taken to correct their deformity. Anterior osteotomy with or without posterior instrumentation were performed in 31 patients (Group 1). Pedicle subtraction osteotomies were performed in 4 patients (Group 2). For Group 1, the mean angular correction achieved in this was 27.7° (range 9.0-66.0°) and the mean translational correction was 1.8 cm (range 0.1-2.4 cm). In group 2, the mean angular correction was 48.8° (range 38.4-68.3°) and the mean translational correction was 2.8 cm per PSO (range 0.1-5.6 cm). Similar improvements in pre- and post-operative Neck Disability Index scores were achieved with either osteotomy technique. CONCLUSIONS: We present our series of patients with cervical myelopathy and/or radiculopathy and concurrent cervical deformity who were treated with cervical osteotomies. The re-alignment of the spine was a key step in preventing the progression of myelopathy and protecting the spinal cord from the continued injury.

Gout-Induced Cervical Deformity and Progressive Myelopathy Mimicking Infection Requiring Cervical Reconstruction.

BACKGROUND: This study describes a rare case where gout, a condition primarily associated with joint inflammation, initially manifested as a progressive cervical kyphotic deformity, mimicking infection and causing myelopathy. The patient, a previously healthy 56-year-old woman, presented with severe jaw pain and a temporomandibular joint abscess, alongside 2 months of worsening balance and arm/hand tingling. Extensive clinical and radiographic assessments revealed a severe cervical kyphotic deformity with bony erosion at multiple vertebral levels, raising suspicion of an infectious cause of compressive myelopathy. METHODS: The patient underwent an urgent staged surgical intervention involving multilevel cervical decompression and fusion, coupled with cervical deformity correction. RESULTS: Post surgery, she received antibiotics for 7 days, during which pathologic analysis unveiled collections of macrophages reacting to urate crystal deposition in a pattern consistent with gouty tophus. This unexpected diagnosis marked a novel case of undiagnosed gout-induced severe cervical deformity presenting with myelopathic symptoms and successfully managed through cervical spine deformity correction. CONCLUSIONS: This report underscores the significance of considering gout as a potential cause when encountering unusual spinal pathologies, especially in cases where gout-related symptoms are atypical. The presented 540-degree surgical approach effectively addressed both the cervical deformity and gout-induced myelopathic symptoms. To the best of our knowledge, this study represents the first documented instance of a patient with undiagnosed gout-induced severe cervical deformity successfully treated through cervical spine deformity correction, emphasizing the importance of vigilance and innovative management approaches in such rare clinical scenarios. As of the 2-year follow-up, the patient exhibited significant symptom improvement and overall well-being.

Video-Assisted Thoracoscopic Lateral Interbody Fusion for Symptomatic Pseudarthrosis in Neurofibromatosis 1-Associated Spinal Deformity.

BACKGROUND: The treatment of symptomatic pseudarthrosis via posterior-only approaches in the setting of neurofibromatosis 1 (NF1) is challenging due to dural ectasias, resulting in erosion of the posterior elements. The purpose of this report is to illustrate a minimally invasive method for performing anterior thoracic fusion for pseudarthrosis in a patient with NF1-associated scoliosis and dysplastic posterior elements. To the best of our knowledge, this is the first documented case of using video-assisted thoracoscopic lateral interbody fusion to treat pseudarthrosis for NF1-associated spinal deformity. CASE DESCRIPTION: The patient underwent video-assisted thoracoscopic anterior spinal fusion via a direct lateral interbody approach with interbody cage placement at T10-T11 and T11-T12, followed by revision of his posterior spinal fusion and instrumentation. The patient had an uneventful postoperative course. At 6 months of follow-up, the patient had complete resolution of his preoperative symptoms and had returned to full-time work with no complaints. At 3 years postoperatively, the patient reported being satisfied with the operation and had continued to work full-time without restrictions. CONCLUSIONS: To the best of our knowledge, this is the first report of pseudarthrosis in the setting of NF1-associated scoliosis treated via minimally invasive anterior thoracic fusion facilitated by video-assisted thoracoscopic surgery. This is a powerful technique that allows for safe access for anterior thoracic fusion in the setting of dysplastic posterior anatomy and poor posterior bone stock.

Does Pedicle Morphology Affect the Safety and Accuracy of Pedicle Screw Placement Using 3D-Printed Guides? A 5-Year, Single-Center Experience With 2210 Screws Placed for Adult Spinal Deformity Reconstruction.

BACKGROUND: Adult spinal deformity (ASD) surgery often involves the placement of pedicle screws using various methods, including freehand technique, fluoroscopic guidance, and computer-assisted intraoperative navigation, each with distinct limitations. Particularly challenging is the instrumentation of pedicles with small or absent cancellous channels (Watanabe types C and D pedicles), commonly found at the apex of large curves where precise screw placement is crucial for effective deformity correction. 3D-printed pedicle screw drill guides (3DPSG) may assist in accurately placing pedicle screws while minimally disrupting the standard ASD surgery workflow. This study aims to evaluate the safety and efficacy of 3DPSG in ASD patients with Watanabe types C and D pedicles, where the safe corridor for screw placement is limited. METHODS: 3DPSG were designed using fine cut (≤1.25 mm) computed tomography scans. Preoperative screw trajectory planning and guide manufacturing were conducted using computer-aided design software (Mighty Oak Medical, Englewood, CO). Four ASD surgeons with varying experience levels placed the guides. Data on patient demographics, pedicle morphology, number of levels instrumented, and implant-related complications were collected. RESULTS: The study included 115 patients (median age 67, range 18-81 years) with 2210 screws placed from T1 to L5. The median number of levels instrumented per case was 11 (range 7-12). Diagnoses included adult degenerative scoliosis (n = 62), adult idiopathic scoliosis (n = 30), Scheuermann's kyphosis (n = 2), and other complex conditions (n = 21). The overall accuracy rate for pedicle screw placement was 99.5%, with a 0% malposition rate in type C and D pedicles. No vascular or neurological complications or reoperations related to screw placement were reported. CONCLUSION: 3DPSG facilitates safe and accurate pedicle screw placement regardless of pedicle morphology in ASD surgeries. This includes the challenging Watanabe types C and D pedicles, typically found at curve apices, enabling surgeons to achieve high implant density and optimal spinal fixation in ASD patients.

Is spinopelvic mismatch associated with increased disability at 2 years following short-segment lumbar fusions?

OBJECTIVE: This study aimed to investigate the impact of pelvic incidence (PI) and lumbar lordosis (LL) matching on health-related quality of life (HRQOL) outcomes in patients undergoing one- or two-level lumbar fusions for degenerative pathology. The study also examined changes in alignment and HRQOL over a 24-month follow-up period. METHODS: A retrospective cohort study used data from a multicenter, prospectively collected database. Radiographic parameters were measured preoperatively and at 3-month and 24-month postoperative time points. Patients were categorized as having alignment (PI-LL ≤ 10°) or malalignment (PI-LL > 10°) at all time points. The Oswestry Disability Index scores were collected at the same time points. Statistical analyses assessed differences in HRQOL scores and radiographic parameters between the aligned and malaligned groups. RESULTS: Seventy-six patients were included. Both the aligned and malaligned groups showed improved HRQOL scores after surgery, but patients with proper alignment (PI-LL ≤ 10°) had significantly better HRQOL scores at the 24-month follow-up. Alignment remained stable from 3 months to 24 months postoperatively, with minimal movement between the aligned and malaligned groups. CONCLUSIONS: Proper PI-LL matching in one- and two-level lumbar fusions for degenerative pathology leads to improved HRQOL outcomes at the 24-month follow-up. Patients with maintained proper alignment after surgery experience continued improvement in disability levels. Surgeons should consider longer follow-up for patients who do not achieve proper alignment initially, as 24 months is crucial for assessing the consequences of malalignment in short-segment lumbar fusions.

Describing Functional Low Back Pain Disability in the American Population: A Crowd-sourced Evaluation of the Oswestry Disability Index.

BACKGROUND CONTEXT: The Oswestry Disability Index (ODI) is widely utilized as a patient reported outcome (PRO) tool to assess patients presenting with low back pain (LBP) and following thoracolumbar spine surgery. No primary study has calculated the baseline range of ODI values in the diverse American population. Establishing age-adjusted normative values for ODI in the American population is crucial for assessing the utility of treatment strategies. PURPOSE: The purpose of this study is to describe the baseline range of functional low back disability as measured by the ODI in an American population. STUDY DESIGN/SETTING: Cross-Sectional Observational Study. PATIENT SAMPLE: A total of 1214 participants were recruited from the United States in January 2024 using a combination of the Connect and PrimePanel platforms by CloudResearch to complete a survey administered on a RedCap online database. The survey consisted of 10 demographic questions and the 10 ODI survey questions. The distribution of the survey was designed to obtain approximately 100 respondents in each of the following age groups: 18-29, 30-39, 40-49, 50-59, 60-69, 70-79, and 80-89. The distribution of the sample was similarly designed to match the US Census racial data with 78.1% White, 13.9% Black, and 7.9% other. OUTCOME MEASURES: Oswestry Disability Index (ODI). METHODS: A crowd-sourcing platform called Cloudresearch was used to collect a representative sample of the US population by answering questions of the Oswestry Disability Questionnaire (ODQ), a 10-question survey. RESULTS: The final sample size was 797 participants including 386 (48.4%) males and 411 (51.6%) females; 169 participants were excluded that did not complete the survey and an additional 248 were excluded for failing attention check questions. The overall mean ODI score for the combined age groups was 14.35 (95% CI [13.33, 15.37]). The mean ODI scores increased with age, with the highest mean ODI in ages 70-79 at 18.0 (95% CI [14.76, 21.24]). Female participants reported higher mean ODI scores than their male counterparts in the 18-29 age group (P = .01), 50-59 age group (P = .01), and 60-69 age group (P = .02). Additionally, a weak positive correlation was found between Body Mass Index (BMI) and ODI scores (r = 0.22, P < .001). CONCLUSION: Our findings demonstrate a clear trend of increased disability with age. This study describes the baseline range of functional low back pain disability in the US population. By defining these parameters, healthcare professionals can better tailor age and sex-specific interventions to manage disability in the aging U.S. population, ultimately improving patient care and both operative and non-operative treatment plans for LBP-related thoracolumbar pathology.

Are Variable Screw Angle Change and Screw-to-Vertebral Body Ratio Associated With Radiographic Subsidence Following Anterior Cervical Discectomy and Fusion?

STUDY DESIGN: Retrospective Cohort. OBJECTIVE: This study aims to assess the easily measurable radiographic landmarks of screw-to-vertebral body ratio and changes in screw angle to identify if they are associated with early subsidence following an Anterior cervical discectomy and fusion (ACDF). METHODS: A retrospective cohort study was conducted on patients undergoing 1-3 level ACDF with allograft or PEEK cages. Preoperative, immediate postoperative, and 6-month postoperative radiographs were analyzed to measure intradiscal height (or distance between 2 vertebral bodies) as an anterior vertebral distance (AVD), middle (MVD), and posterior (PVD), screw angle, screw-to-vertebral body length ratio, and interscrew distance. Multivariate stepwise regression analyses were performed. RESULTS: 92 patients were included (42 single-level, 32 two-level, and 18 3-level ACDFs). In single-level ACDFs, a decrease in the caudal screw angle was associated with a decrease in AVD (=.001) and MVD (P = .03). A decrease in the PVD was associated with a decrease in segmental lordosis (P < .001). For two-level ACDFs, a higher caudal screw-to-body ratio was associated with a lower MVD (P = .01). CONCLUSION: Six months following an ACDF for degenerative pathology, a decrease in the caudal screw angle was associated with an increase in radiographic subsidence at the antero-medial aspect of the disc space albeit largely subclinical. This suggests that the caudal screw angle change may serve as a reliable radiographic marker for early radiographic subsidence. Furthermore, a greater screw-to-vertebral body ratio may be protective against radiographic subsidence in two-level ACDF procedures.

Monthly multidisciplinary complex spine conference: a cost-analysis utilizing time-driven activity-based costing.

PURPOSE: To understand costs and provide an initial framework associated with conference implementation as it pertains to complication prevention. METHODS: Team members' time spent on conference preparation, presentation, and follow-up tasks was recorded and averaged to determine the time required to prepare and present one patient. Using 2022 hourly wage rates based on our urban hospital setting, wage values were calculated for each personnel type and applied to their time spent. The total cost of the conference was annualized and calculated from the time spent in the three phases of the conference multiplied by the wage rate. Published data on complication rates and associated costs before and after conference implementation were used to calculate total cost reduction. RESULTS: With 3 active spine surgeons and 108 patients per year, the total time investment was 104.04 min per patient, costing $21,791 annually. Total RN equivalent value per patient was 5.25 for all three phases. Using a historical model, this multidisciplinary approach for adult spinal deformity reduced complications by 51% at 30 days, resulting in cost savings of $418,518 per year. Thus, the model demonstrates that implementation of this approach resulted in a potential total savings of $396,726/year. CONCLUSION: Implementing a cost-saving tool for managing complex spinal disorders is a responsibility of the spine team, who should lead a multidisciplinary conference. The combination of TDABC and lean methodology can effectively demonstrate the variable costs associated with this multidisciplinary effort and models provide evidence of potential cost-savings when applied to a multidisciplinary adult spinal deformity conference. These findings should encourage clinicians and administrators to allocate resources to improve patient care by reducing complications and costs.

Personalized Medicine in Orthopaedic Surgery: The Case of Spine Surgery.

Personalized medicine has made a tremendous impact on patient care. Although initially, it revolutionized pharmaceutical development and targeted therapies in oncology, it has also made an important impact in orthopaedic surgery. The field of spine surgery highlights the effect of personalized medicine because the improved understanding of spinal pathologies and technological innovations has made personalized medicine a key component of patient care. There is evidence for several of these advancements to support their usage in improving patient care. Proper understanding of normative spinal alignment and surgical planning software has enabled surgeons to predict postoperative alignment accurately. Furthermore, 3D printing technologies have demonstrated the ability to improve pedicle screw placement accuracy compared with free-hand techniques. Patient-specific, precontoured rods have shown improved biomechanical properties, which reduces the risk of postoperative rod fractures. Moreover, approaches such as multidisciplinary evaluations tailored to specific patient needs have demonstrated the ability to decrease complications. Personalized medicine has shown the ability to improve care in all phases of surgical management, and several of these approaches are now readily available to orthopaedic surgeons.

Incidence, etiology and time course of delays to adult spinal deformity surgery: a single-center experience.

PURPOSE: We sought to determine the incidence, origin, and timeframe of delays to adult spinal deformity surgery so that institutions using preoperative multidisciplinary patient assessment teams might better anticipate and address these potential delays. METHODS: Complex spine procedures for treatment of adult spinal deformity from 1/1/18 to 8/31/21 were identified. Procedures for infection, tumor, and urgent/emergent cases were excluded. Operations delayed due to COVID or those that were performed outside of our established perioperative care pathway were also excluded. The electronic health record was used to identify the etiology and timeline of all pre- and peri-operative delays. RESULTS: Of 235 patients scheduled for complex spine surgery, 193 met criteria for inclusion. Of these patients, 35 patients experienced a surgical delay (18.1%) with a total of 41 delays recorded. Reasons for delay include medically unoptimized (25.6%), intraoperative complication (17.9%), patient directed delay (17.9%), patient illness/injury (15.4%), scheduling complication (10.3%), insurance delay/denial (5.1%), and unknown (2.6%). Twenty-four delays experienced by 22 individuals occurred within 7 days of their scheduled surgery date. CONCLUSION: At a single multidisciplinary center, most delays to adult spinal deformity surgery occur before a patient is admitted to the hospital, and for recommendations of additional medical workup/clearance. We suspect that the preoperative protocol might increase pre-admission delays for unoptimized patients, as the protocol is intended to ensure patients receive surgery only when they are medically ready. Further research is needed to determine the economic and system impact of delays related to a preoperative optimization protocol weighed against the reduction in adverse events these protocols can provide.

What is the fate of the adjacent segmental angles 6 months after single-level L3-4 or L4-5 lateral lumbar interbody fusion?

BACKGROUND CONTEXT: Lateral lumbar interbody fusion (LLIF) is an effective technique for fusion and sagittal alignment correction/maintenance. Studies have investigated the impact on the segmental angle and lumbar lordosis (and pelvic incidence-lumbar lordosis mismatch), however not much is documented regarding the immediate compensation of the adjacent angles. PURPOSE: To evaluate acute adjacent and segmental angle as well as lumbar lordosis changes in patients undergoing a L3-4 or L4-5 LLIF for degenerative pathology. STUDY DESIGN/SETTING: Retrospective cohort study. PATIENT SAMPLE: Patients included in this study were analyzed pre- and post-LLIF performed by one of three fellowship-trained spine surgeons, 6 months following surgery. OUTCOME MEASURES: Patient demographics (including body mass index, diabetes diagnosis, age, and sex) as well as VAS and ODI scores were measured. Lateral lumbar radiograph parameters: lumbar lordosis (LL), segmental lordosis (SL), infra and supra-adjacent segmental angle, and pelvic incidence (PI). METHODS: Multiple regressions were applied for the main hypothesis tests. We examined any interactive effects at each operative level and used the 95% confidence intervals to determine significance: a confidence interval excluding zero indicates a significant effect. RESULTS: We identified 84 patients who underwent a single level LLIF (61 at L4-5, 23 at L3-4). For both the overall sample and at each operative level, the operative segmental angle was significantly more lordotic postop compared to preop (all ps≤.01). Adjacent segmental angles were significantly less lordotic postop compared to pre-op overall (p=.001). For the overall sample, greater lordotic change at the operative segment led to more compensatory reduction of lordosis at the supra-adjacent segment. At L4-5, more lordotic change at the operative segment led to more compensatory lordosis reduction at the infra-adjacent segment. CONCLUSION: The present study demonstrated that LLIF resulted in significant increase in operative level lordosis and a compensatory decrease in supra- and infra-adjacent level lordosis, and subsequently no significant impact on spinopelvic mismatch.

Early Compensatory Segmental Angle Changes at L3-4 and L4-5 Following a L5-S1 Interbody Fusion for a Grade 1 Spondylolisthesis.

STUDY DESIGN: Retrospective study included patients who underwent a L5-S1 ALIF or TLIF with posterior pedicle screw instrumentation for grade 1 spondylolisthesis 2018-2022. OBJECTIVE: To compare early reciprocal changes at the L3-4 and L4-5 adjacent levels six months after anterior (ALIF) or transforaminal (TLIF) lumbar interbody fusion at L5-S1. BACKGROUND: Degenerative and chronic isthmic spondylolistheses often result in decreased segmental lordosis at L5-S1. This can lead to lordotic overcompensation at adjacent levels to maintain spinopelvic balance. However, the fate of adjacent angles following interbody fusion is not well understood. METHODS: Preoperative and 6-month postoperative measurements of segmental lordosis (L3-4, L4-5, and L5-S1), lumbar lordosis, and pelvic incidence were obtained from sagittal standing radiographs. Preliminary t-tests were performed for descriptive purposes, and multiple regression was used for hypothesis testing. RESULTS: Ninety-eight patients met the inclusion criteria (50 ALIF and 48 TLIF). A greater amount of lordosis achieved at L5-S1 was significantly associated with a greater reduction of segmental lordosis at L4-5 (r=-0.65, P<.001) or L3-4 (r=-0.46, P<.001) (Fig. 3A). A greater preoperative PI was associated with a greater reduction of segmental lordosis at L4-L5 (r=-0.42, P<.001) and at L3-L4 (r=-0.44, P<.001). CONCLUSION: At six months following a lumbar interbody fusion at L5-S1, greater compensatory changes with lordosis reduction are observed at the supra-adjacent L4-5 and L3-4 levels in patients achieving greater L5-S1 segmental lordosis. Additionally, preoperative pelvic incidence (PI) played a role in influencing lordotic correction.

Clinical Guidelines for the Evaluation and Treatment of Lumbar Disc Herniations: How Accurate is the Internet?

OBJECTIVE: To compare information online regarding lumbar disc herniation (LDH) on commonly searched websites and compare those findings with the evidence-based recommendations listed in the North American Spine Society (NASS) clinical practice guidelines. METHODS: NASS Clinical Practice Guidelines, Internet searches were performed utilizing three common search engines (Google, Bing, Yahoo) and keywords associated with LDH. The top 20 websites from each search were selected. The content regarding diagnosis and treatment of LDH was compared to the NASS clinical practice guidelines. RESULTS: On average, websites mentioned only 59% of recommendations supported by Level I evidence. Websites included an average of 3 recommendations not discussed in the NASS guidelines out of an average of 12 total recommendations. Muscle and sensory testing and physical therapy were the most frequent recommendations, appearing on over 80% of websites. Websites were equally likely to contain recommendations backed by high-quality evidence as recommendations not included in NASS guidelines. CONCLUSIONS: This study demonstrates that websites regarding LDH contain a mix of information, with only a fraction of recommendations aligning with NASS clinical guidelines. Patients who use these websites are presented with unsubstantiated information, conceivably impacting their understanding, expectations and decision-making in physician offices.

Direct membrane association drives mitochondrial fission by the Parkinson disease-associated protein alpha-synuclein.

The protein α-synuclein has a central role in Parkinson disease, but the mechanism by which it contributes to neural degeneration remains unknown. We now show that the expression of α-synuclein in mammalian cells, including neurons in vitro and in vivo, causes the fragmentation of mitochondria. The effect is specific for synuclein, with more fragmentation by α- than ß- or γ-isoforms, and it is not accompanied by changes in the morphology of other organelles or in mitochondrial membrane potential. However, mitochondrial fragmentation is eventually followed by a decline in respiration and neuronal death. The fragmentation does not require the mitochondrial fission protein Drp1 and involves a direct interaction of synuclein with mitochondrial membranes. In vitro, synuclein fragments artificial membranes containing the mitochondrial lipid cardiolipin, and this effect is specific for the small oligomeric forms of synuclein. α-Synuclein thus exerts a primary and direct effect on the morphology of an organelle long implicated in the pathogenesis of Parkinson disease.

Popliteal venotomy during posterior cruciate ligament reconstruction in the setting of a popliteal artery bypass graft.

Injury to the vascular structures in the popliteal fossa during arthroscopic cruciate ligament reconstruction can be limb threatening or even life threatening. We present the first report, to our knowledge, of an isolated injury to a popliteal vein during arthroscopic posterior cruciate ligament reconstruction. Unfortunately, the venotomy led to cardiopulmonary arrest and flash pulmonary edema in this patient. Preoperative planning is paramount to assess risk of injury to vascular structures, which may be increased in patients who have had prior procedures on the affected knee. Furthermore, vascular surgery consultation preoperatively after a magnetic resonance angiogram or venogram and avoiding the use of epinephrine in the arthroscopy fluid should be considered when performing these higher-risk procedures.