Letter to the editor: "Effect of electrical stimulation on the fusion rate after spinal surgery: a systematic review and meta-analysis".

This letter provides feedback on the article Effect of electrical stimulation on the fusion rate after spinal surgery: a systematic review and meta-analysis. The study highlights the clinical efficacy of electrical stimulation (ES) in enhancing fusion rates post-surgery. Future research should focus on identifying optimal ES parameters, long-term safety profiles, and its personalized application based on genetic and metabolic factors. Additionally, exploring the combination of ES with other regenerative therapies and evaluating its cost-effectiveness could further improve clinical outcomes.

L4-L5 anatomy classification system for lateral lumbar interbody fusion.

Lateral lumbar interbody fusion (LLIF), developed by Dr. Luiz Pimenta in 2006, allows access to the spinal column through the psoas major muscle. The technique has many advantages, such as reduced bone and muscular tissue damage, indirect decompression, larger implants, and lordosis correction capabilities. However, this technique also has drawbacks, with the most notorious being the risk of spinal pathologies due to indirect injury of the lumbar plexus, but with low rates of persistent injuries. Therefore, several groups have proposed classifications to help identify patients at a greater risk of presenting with neurological deficits. The present work proposes a classification system that relies on simple observation of easily identifiable key structures to guide lateral L4-L5 LLIF decision-making. Patients aged > 18 years who underwent preoperative magnetic resonance imaging (MRI) between 2022 and 2023 were included until 50 high-quality images were acquired. And excluded as follow Anatomical changes in the vertebral body or major psoas muscles prevent the identification of key structures or poor-quality MRIs. Each anatomy was classified as type I, type II, or type III according to the consensus among the three observers. Fifty anatomical sites were included in this study. 70% of the L4-L5 anatomy were type I, 18% were type II, and 12% were type III. None of the type 3 L4-L5 anatomies were approached using a lateral technique. The proposed classification is an easy and simple method for evaluating the feasibility of a lateral approach to-L4-L5.

Evaluation of the use of tranexamic acid in the postoperative period in patients with scoliosis undergoing posterior fusion.

Scoliosis is the most prevalent type of spinal deformity, with a 2-3% prevalence in the general population. Moreover, surgery for scoliotic deformity may result in severe blood loss and, consequently, the need for blood transfusions, thereby increasing surgical morbidity and the rate of complications. Several antifibrinolytic drugs, such as tranexamic acid, have been regarded as safe and effective options for reducing blood loss. Therefore, the present study aimed to analyse the effectiveness of this drug for controlling bleeding when used intraoperatively and in the first 48 h after surgery. A prospective randomized study of a cohort of patients included in a mass event for scoliosis treatment using PSF was performed. Twenty-eight patients were analysed and divided into two groups: 14 patients were selected for intraoperative and postoperative use of tranexamic acid (TXA), and the other 14 were selected only during the intraoperative period. The drainage bleeding rate, length of hospital stay, number of transfused blood units, and rate of adverse clinical effects were compared. All the patients involved had similar numbers of fusion levels addressed and similar scoliosis profiles. The postoperative bleeding rate through the drain did not significantly differ between the two groups (p > 0.05). There was no significant difference in the number of transfused blood units between the groups (p = 0.473); however, in absolute numbers, patients in the control group received more transfusions. The length of hospital stay was fairly similar between the groups, with no statistically significant difference. Furthermore, the groups had similar adverse effects (p = 0.440), with the exception of nausea and vomiting, which were twice as common in the TXA group postoperatively than in the control group. No significant differences were found in the use of TXA during the first 48 postoperative hours or in postoperative outcomes.

Survey of major complications after prone transpsoas surgery: an analysis of early adopters' practice.

INTRODUCTION: The prone transpsoas technique (PTP) is a modification of the traditional lateral lumbar interbody fusion approach, which was first published in the literature in 2020. The technique provides several advantages, such as lordosis correction and redistribution, single-position surgery framework, and ease of performing posterior techniques when needed. However, the prone position also leads to the movement of some retroperitoneal, vascular, and neurological structures, which could impact the complication profile. Therefore, this study aimed to investigate the occurrence of major complications in the practice of early adopters of the PTP approach. METHODS: A questionnaire containing 8 questions was sent to 50 participants and events involving early adopters of the prone transpsoas technique. Of the 50 surgeons, 32 completed the questionnaire, which totaled 1963 cases of PTP surgeries. RESULTS: Nine of the 32 surgeons experienced a major complication (28%), with persistent neurological deficit being the most frequent (7/9). Of the total number of cases, the occurrence of permanent neurological deficits was approximately 0,6%, and the rate of vascular and visceral injuries were both 0,05% (1/1963 for each case). CONCLUSION: Based on the analysis of the questionnaire responses, it can be concluded that PTP is a safe technique with a very low rate of serious complications. However, future studies with a more heterogeneous group of surgeons and a more rigorous linkage between answers and patient data are needed to support the findings of this study.

Navigated Anterior Full-Endoscopic Transcervical Approach Odontoidectomy for Traumatic Posterior Atlantoaxial Dislocation Without Odontoid Fracture.

BACKGROUND AND IMPORTANCE: Complete posterior atlantoaxial dislocation (PAAD) with an unfractured odontoid process is a rare condition where a dislocated but intact odontoid process is positioned ventrally to the anterior arch of C1. This lesion is related to transverse and alar ligament rupture secondary to hyperextension and rotatory traumatic injury and is often associated with neurological deficit. The treatment strategy remains controversial, and in many cases, odontoidectomy is required. Traditional approaches for odontoidectomy (transnasal and transoral) are technically demanding and are related to several complications. This article describes a 360° reduction and stabilization technique through a navigated anterior full-endoscopic transcervical approach (nAFETA) as a novel technique for odontoidectomy and C1-C2 anterior transarticular fixation supplemented with posterior fusion. CLINICAL PRESENTATION: A 21-year-old man presented to the emergency room by ambulance after a motorcycle accident. On evaluation, incomplete ASIA B spinal cord injury was documented. Imaging revealed a complete PAAD. We performed a two-staged procedure, a nAFETA odontoidectomy plus C1-C2 anterior transarticular fixation followed by posterior C1-C2 wired fusion. At a 2-year follow-up, the patient had a 10-point Oswestry Disability Index score and neurological improvement to ASIA E. CONCLUSION: PAAD can be successfully treated through minimally invasive nAFETA. Noteworthy, the risks of the transoral and endonasal routes were avoided through this approach. In addition, nAFETA allows anterior transarticular fixation during the same procedure providing spinal stability. Further studies are required to expand the use of nAFETA in this field.

Comparison of perioperative outcomes in obese and non-obese patients subjected to open lumbar spine surgery.

OBJECTIVE: Obesity is a global epidemic affecting developing countries. The relationship between obesity and perioperative outcomes during elective lumbar spine surgery remains controversial, especially in those without morbid disease. MATERIALS AND METHODS: We retrospectively revised the medical records of patients with lumbar spine degeneration subjected to elective surgery. The data retrieved included demographic and clinical characteristics, body mass index (BMI), obesity status (BMI ≥ 30), surgical interventions, estimated blood loss (EBL), operative time, length of stay (LOS), and post-operative complications. Perioperative outcomes were compared between Grade I-II obese and non-obese individuals. RESULTS: We enrolled 53 patients, 18 with Grade I-II obesity. Their median age was 51, with no differences in gender, comorbidities, laboratory parameters, and surgical procedures received between groups. No clinically relevant differences were found between grade I-II obese and non-obese participants in EBL (300 mL vs. 250 mL, p = 0.069), operative time (3.2 h vs. 3.0 h, p = 0.037), and LOS (6 days vs. 5 days, p = 0.3). Furthermore, BMI was not associated with the incidence of significant bleeding and long stay but showed a modest correlation with operative time. CONCLUSION: Grade I-II obesity does not increase surgical complexity nor perioperative complications during open lumbar spine surgery.

OBJETIVO: La obesidad es una epidemia mundial que afecta a países subdesarrollados. Su relación con los resultados de la cirugía de columna lumbar electiva sigue siendo controvertida, especialmente en obesos sin enfermedad mórbida. MÉTODOS: Se revisaron los expedientes de pacientes con degeneración de la columna lumbar sometidos a cirugía. Los datos recuperados incluyeron características demográficas y clínicas, índice de masa corporal (IMC), estado de obesidad (IMC > 30), intervenciones quirúrgicas, sangrado estimado, tiempo operatorio, tiempo de estancia y complicaciones. Los resultados se compararon entre individuos obesos grado I-II y controles. RESULTADOS: Se incluyeron 53 pacientes, 18 con obesidad de grado I-II. La edad media fue de 51 años, sin diferencias en el sexo, las comorbilidades, los parámetros de laboratorio y los procedimientos quirúrgicos recibidos entre grupos. No se encontraron diferencias relevantes entre los participantes obesos y los no obesos en sangrado (300 vs. 250 mL, p = 0.069), tiempo operatorio (3.2 vs. 3.0 horas, p = 0.037) y estancia (6 vs. 5 días, p = 0.3). El IMC no se asoció con hemorragia y larga estancia, pero mostró una correlación modesta con el tiempo operatorio. CONCLUSIONES: La obesidad grado I-II no predispone a complicaciones durante la cirugía de columna lumbar.

Intra-abdominal Content Movement in Prone Versus Lateral Decubitus Position Lateral Lumbar Interbody Fusion (LLIF).

STUDY DESIGN: A prospective, anatomical imaging study of healthy volunteer subjects in accurate surgical positions. OBJECTIVE: To establish if there is a change in the position of the abdominal contents in the lateral decubitus (LD) versus prone position. SUMMARY OF BACKGROUND DATA: Lateral transpsoas lumbar interbody fusion (LLIF) in the LD position has been validated anatomically and for procedural safety, specifically in relation to visceral risks. Recently, LLIF with the patient in the prone position has been suggested as an alternative to LLIF in the LD position. MATERIALS AND METHODS: Subjects underwent magnetic resonance imaging of the lumbosacral region in the right LD position with the hips flexed and the prone position with the legs extended. Anatomical measurements were performed on axial magnetic resonance images at the L4-5 disc space. RESULTS: Thirty-four subjects were included. The distance from the skin to the lateral disc surface was 134.9 mm in prone compared with 118.7 mm in LD ( P <0.0001). The distance between the posterior aspect of the disc and the colon was 20.3 mm in the prone compared with 41.1 mm in LD ( P <0.0001). The colon migrated more posteriorly in relation to the anterior margin of the psoas in the prone compared with LD (21.7  vs . 5.5 mm, respectively; P <0.0001). 100% of subjects had posterior migration of the colon in the prone compared with the LD position, as measured by the distance from the quadratum lumborum to the colon (44.4  vs . 20.5 mm, respectively; P <0.001). CONCLUSION: There were profound changes in the position of visceral structures between the prone and LD patient positions in relation to the LLIF approach corridor. Compared with LD LLIF, the prone position results in a longer surgical corridor with a substantially smaller working window free of the colon, as evidenced by the significant and uniform posterior migration of the colon. Surgeons should be aware of the potential for increased visceral risks when performing LLIF in the prone position. LEVEL OF EVIDENCE: Level II-prospective anatomical cohort study.

[Comparison of cervical fusion with autografting of fibula vs titanium cage]. / Comparación de artrodesis cervical mediante autoinjerto de peroné frente a caja de titanio.

Background: The anterior cervical discectomy and fusion (ACDF) is the gold standard in the treatment of cervical compression pathology and the titanium cage for fusion represents the most used procedure at an institutional level. A technique using fibular autograft has been described, with good results, lower morbidity and lower cost. Objective: To compare the rate of fusion, subsidence and functional clinical results after discectomy with titanium cage and fibular autograft. Material and methods: A clinical trial with follow-up at 3 and 6 months was carried out in patients diagnosed with cervical spondylosis, candidates for ACDF. 2 groups were formed: fibular autograft and titanium cage. Pre and post functional evaluation using the cervical disability score was made, as well as radiographic fusion and subsidence evaluation. Descriptive statistics, Fisher's exact test, t-test and ANOVA were obtained, establishing p < 0.05. Results: A sample of 20 patients with an average age of 56 years was obtained, finding a fusion rate of 90% for fibular autograft and 30% for titanium (p = 0.02) at 3 months. 10% of patients with fibular autograft presented subsidence and 70% with titanium cage at 3 and 6 months (p = 0.02). In the functional results was not found difference between both procedures (p = 0.874). Conclusions: The use of autologous fibular graft offers a better rate of fusion and subsidence compared to the titanium cage, as well as similar functional results at 3 months of follow-up. It represents an excellent treatment option for cervical spondylosis.

Introducción: la disectomía cervical anterior y fusión (ACDF) es el estándar de oro en el tratamiento de la patología compresiva cervical. La caja de titanio para artrodesis es el procedimiento más usado a nivel institucional. Se ha descrito una técnica con autoinjerto de peroné, con buenos resultados, menor morbilidad y menor costo. Objetivo: comparar la tasa de fusión, subsidencia y resultados clínicos funcionales posteriores a disectomía con caja de titanio y autoinjerto de peroné. Material y métodos: ensayo clínico con seguimiento a tres y seis meses en pacientes con diagnóstico de espondilosis cervical, candidatos a ACDF. Se formaron dos grupos: autoinjerto de peroné y caja de titanio. Se hizo evaluación funcional antes y después mediante la escala de discapacidad cervical, y evaluación de fusión y subsidencia radiográficas. Se usó estadística descriptiva, prueba exacta de Fisher, prueba t y ANOVA, estableciendo una p < 0.05. Resultados: se obtuvo una muestra de 20 pacientes con promedio de 56 años; hubo una tasa de fusión del 90% para autoinjerto de peroné y 30% para titanio (p = 0.02) a los tres meses. De los pacientes con autoinjerto de peroné, 10% presentaron subsidencia y un 70% con caja de titanio a los tres y seis meses (p = 0.02). No se encontró diferencia en los resultados funcionales a tres y seis meses de ambos procedimientos. Conclusiones: el uso de injerto autólogo de peroné ofrece mejor tasa de fusión y subsidencia en comparación con la caja de titanio, así como resultados funcionales similares a los tres meses. Es una excelente opción para tratar la espondilosis cervical.

Are Clinical or Surgical Outcomes Different Based on Whether the Same Surgeon or Hospital System Performs the Spine Revision?

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine the effects of discontinuity in care by changing surgeons, health systems, or increased time to revision surgery on revision spine fusion surgical outcomes and patient-reported outcomes. SUMMARY OF BACKGROUND INFORMATION: Patients undergoing revision spine fusion experience worse outcomes than those undergoing primary lumbar surgery. Those requiring complex revisions are often transferred to tertiary or quaternary referral centers under the assumption that those institutions may be more accustomed at performing those procedures. However, there remains a paucity of literature assessing the impact of discontinuity of care in revision spinal fusions. METHODS: Patients who underwent revision 1-3 level lumbar spine fusion 2011-2021 were grouped based on (1) revision performed by the index surgeon versus a different surgeon, (2) revision performed within the same versus different hospital system as the index procedure, and (3) length of time from index procedure. Multivariate regression for outcomes controlled for confounding differences. RESULTS: A total of 776 revision surgeries were included. An increased time interval between the index procedure and the revision surgery was predictive of a lower risk for subsequent revision procedure (odds ratio: 0.57, P =0.022). Revision surgeries performed by the same surgeon predicted a reduced length of hospital stay (ß: -0.14, P =0.001). Neither time to revision nor undergoing by the same surgeon or same practice predicted 90-day readmission rates. Patients are less likely to report meaningful improvement in Mental Component Score-12 or Physical Component Score-12 if revision surgery was performed at a different hospital system. CONCLUSIONS: Patients who have revision lumbar fusions have similar clinical outcomes regardless of whether their surgeon performed the index procedure. However, continuity of care with the same surgeon may reduce hospital length of stay and associated health care costs. The length of time between primary and revision surgery does not significantly impact patient-reported outcomes. LEVEL OF EVIDENCE: Level III.

An Immunologic and Biomechanical Comparison of Polyether Ether Ketone-Zeolite and Polyether Ether Ketone Interbody Fusion Devices.

STUDY DESIGN: A laboratory study comparing polyether ether ketone (PEEK)-zeolite and PEEK spinal implants in an ovine model. OBJECTIVE: This study challenges a conventional spinal implant material, PEEK, to PEEK-zeolite using a nonplated cervical ovine model. SUMMARY OF BACKGROUND DATA: Although widely used for spinal implants due to its material properties, PEEK is hydrophobic, resulting in poor osseointegration, and elicits a mild nonspecific foreign body response. Zeolites are negatively charged aluminosilicate materials that are hypothesized to reduce this pro-inflammatory response when used as a compounding material with PEEK. MATERIALS AND METHODS: Fourteen skeletally mature sheep were, each, implanted with one PEEK-zeolite interbody device and one PEEK interbody device. Both devices were packed with autograft and allograft material and randomly assigned to one of 2 cervical disc levels. The study involved 2 survival time points (12 and 26 weeks) and biomechanical, radiographic, and immunologic endpoints. One sheep expired from complications not related to the device or procedure. A biomechanical evaluation was based on measures of segmental flexibility, using 6 degrees of freedom pneumatic spine tester. Radiographic evaluation was performed using microcomputed tomography scans in a blinded manner by 3 physicians. Levels of the pro-inflammatory cytokines, interleukin (IL)-1ß, IL-6, and tumor necrosis factor-alpha at the implant, were quantified using immunohistochemistry. RESULTS: PEEK-zeolite and PEEK exhibited an equivalent range of motion in flexion extension, lateral bending, and axial torsion. A motion was significantly reduced for implanted devices at both time points as compared with native segments. Radiographic assessments of fusion and bone formation were similar for both devices. PEEK-zeolite exhibited lower levels of IL-1ß ( P = 0.0003) and IL-6 ( P = 0.03). CONCLUSION: PEEK-zeolite interbody fusion devices provide initial fixation substantially equivalent to PEEK implants but exhibit a reduced pro-inflammatory response. PEEK-zeolite devices may reduce the chronic inflammation and fibrosis previously observed with PEEK devices.

Full-endoscopic foraminotomy in low-grade degenerative and isthmic spondylolisthesis: a patient-specific tailored approach.

PURPOSE: To describe the surgical technique and methodology to successfully plan and execute an endoscopic foraminotomy in patients with isthmic or degenerative spondylolisthesis, according to each patient's unique characteristics. METHODS: Thirty patients with degenerative or isthmic spondylolisthesis (SL) with radicular symptoms were included from March 2019 to September 2022. Treating physician registered patients' baseline and imaging characteristics, as well as preoperative back pain VAS, leg pain VAS and ODI. Subsequently, authors treated the included patients with an endoscopic foraminotomy according to a "patient-specific" tailored approach. RESULTS: Nineteen patients (63.33%) had isthmic SL and 11 patients (36.67%) had degenerative SL. 75.86% of the cases had a Meyerding Grade 1 listhesis. One of the transforaminal foraminotomies with lateral recess decompression in degenerative SL had to be aborted because of intense osseous bleeding. Of the remaining 29 patients, one patient experienced recurrence of the sciatica pain that required subsequent reintervention and fusion. No other intraoperative or post-operative complications were observed. None of the patients developed post-operative dysesthesia. In 86.67% of the patients, the foraminotomy was implemented using a transforaminal approach. In the remaining 13.33% of the cases, an interlaminar contralateral approach was used. Lateral recess decompression was performed in half of the cases. Mean follow-up time was 12.69 months, reaching a maximum of 40 months in some patients. Outcome variables such as VAS for leg and back pain, as well as ODI, showed statistically significant reduction since the 3-month follow-up visit. CONCLUSION: In the presented case series, endoscopic foraminotomy achieved satisfactory outcomes without sacrificing segmental stability. The proposed patient-specific "tailored" approach allowed to successfully design and execute the surgical strategy to perform an endoscopic foraminotomy through transforaminal or interlaminar contralateral approaches.

Effect of Clinical and Radiographic Degenerative Spondylolisthesis Classification on Patient-reported Outcomes and Spinopelvic Parameters for Patients With Single-level L4-L5 Degenerative Spondylolisthesis After Lumbar Fusion.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To determine whether preoperative clinical and radiographic degenerative spondylolisthesis (CARDS) classification is associated with differences in patient-reported outcomes and spinopelvic parameters after posterior decompression and fusion for L4-L5 degenerative spondylolisthesis (DS). SUMMARY: The CARDS classification for lumbar DS, an alternative to the Meyerding system, considers additional radiographic findings such as disc space collapse and segmental kyphosis and stratifies DS into 4 radiographically distinct classes. Although CARDS has been shown to be a reliable and reproducible method for classifying DS, very few studies have assessed whether the CARDS types represent distinct clinical entities. PATIENTS AND METHODS: A retrospective cohort analysis was conducted on patients with L4-L5 DS who underwent posterior lumbar decompression and fusion. Changes in spinopelvic alignment and patient-reported outcomes measures, including recovery ratios and percentage of patients achieving the minimal clinically important difference, were compared among patients in each CARDS classification 1-year postoperatively using analysis of variance or Kruskal-Wallis H with Dunn post hoc analysis. Multiple linear regression determined whether CARDS groups significantly predicted patient-reported outcomes measures, lumbar lordosis (LL), and pelvic incidence-lumbar lordosis mismatch (PI-LL) while controlling for demographic and surgical characteristics. RESULTS: Preoperative type B spondylolisthesis predicted decreased improvement in "physical component and mental component score of the short form-12" compared with type A spondylolisthesis (ß-coefficient = -5.96, P = 0.031) at 1 year. Significant differences were found between CARDS groups with regards to ΔLL (A: -1.63 degrees vs B: -1.17 degrees vs C: 2.88 degrees vs D: 3.19 degrees, P = 0.010) and ΔPI-LL (A: 1.02 degrees vs B: 2.09 degrees vs C: -2.59 degrees vs D: -3.70 degrees, P = 0.012). Preoperative type C spondylolisthesis was found to predict increased LL (ß-coefficient = 4.46, P = 0.0054) and decreased PI-LL (ß-coefficient = -3.49, P = 0.025) at 1 year compared with type A spondylolisthesis. CONCLUSIONS: Clinical and radiographic outcomes differed significantly by preoperative CARDS classification type for patients undergoing posterior decompression and fusion for L4-L5 DS. LEVEL OF EVIDENCE: Level III.

Minimally invasive lateral single-position surgery for multilevel degenerative lumbar spine disease: feasibility and perioperative results in a single Latin-American spine center.

INTRODUCTION: Within advances in minimally invasive spine surgery, the implementation of lateral single position (LSP) increases efficiency while limiting complications, avoiding intraoperative repositioning and diminishing surgical time. Most literature describes one-level instrumentation of the lumbar spine; this study includes the use of LSP for multilevel degenerative disease. OBJECTIVE: The objective of the article is to analyze initial clinical results and complications in the use of LSP for multiple level instrumentation in adults with lumbar degenerative disease. METHODS: A retrospective early clinical series was performed for patients who had multiple level instrumentation in LSP between August 2019 and September 2022 at the Hospital Universitario San Ignacio in Bogota, Colombia. Inclusion criteria were patients older than 18 years with symptomatic lumbar degenerative disease, undergoing any combination of multilevel anterior lumbar interbody fusion, lateral lumbar interbody fusion (LLIF) and pedicle screw fixation. RESULTS: Forty patients with an average age of 61.3 years were included, with diagnosis of multilevel degenerative spondylotic changes. Four-, three- and two-level interventions were performed in 52.5, 35 and 12.5%, respectively. Average time per level was 68.9 min, and length of hospital stay had an average of 2.4 days, with all patients starting ambulation within the first postoperative day. CONCLUSION: Procedural time and blood loss were similar to those reported in literature. No severe lesions, postoperative infections or reinterventions took place. Although it was a small number of patients and further clinical trials are needed, LSP for multiple levels is apparently safe with adequate outcomes which may improve efficiency in the operating room.

Clinical Validation of a Novel Musculoskeletal Modeling Framework to Predict Postoperative Sagittal Alignment.

STUDY DESIGN: A retrospective radiographic and biomechanical analysis of 108 thoracolumbar fusion patients from two clinical centers. OBJECTIVE: This study aimed to determine the validity of a computational framework for predicting postoperative patient posture based on preoperative imaging and surgical data in a large clinical sample. SUMMARY OF BACKGROUND DATA: Short-term and long-term studies on thoracolumbar fusion patients have discussed that a preoperative predictive model would benefit surgical planning and improve patient outcomes. Clinical studies have shown that postoperative alignment changes at the pelvis and intact spine levels may negatively affect postural balance and quality of life. However, it remains challenging to predict such changes preoperatively because of confounding surgical and patient factors. MATERIALS AND METHODS: Patient-specific musculoskeletal models incorporated weight, height, body mass index, age, pathology-associated muscle strength, preoperative sagittal alignment, and surgical treatment details. The sagittal alignment parameters predicted by the simulations were compared with those observed radiographically at a minimum of three months after surgery. RESULTS: Pearson correlation coefficients ranged from r=0.86 to 0.95, and mean errors ranged from 4.1° to 5.6°. The predictive accuracies for postoperative spinopelvic malalignment (pelvic incidence minus lumbar lordosis>10°) and sagittal imbalance parameters (TPA>14°, T9PA>7.4°, or LPA>7.2°) were between 81% and 94%. Patients treated with long fusion (greater than five segments) had relatively lower prediction errors for lumbar lordosis and spinopelvic mismatch than those in the local and short groups. CONCLUSIONS: The overall model performance with long constructs was superior to those of the local (one to two segments) and short (three to four segments) fusion cases. The clinical framework is a promising tool in development to enhance clinical judgment and to help design treatment strategies for predictable surgical outcomes. LEVEL OF EVIDENCE: 3.

Comparison of segmental lordosis gain of prone transpsoas (PTP) vs. lateral lumbar interbody fusion.

INTRODUCTION: Lumbar interbody fusion is a standard method to treat certain degenerative conditions that are refractory to conservative treatments. LLIF reduces posterior muscle damage, can relieve neurological symptoms through indirect decompression, provides increased stability with its wider cages, and promotes more significant segmental lordosis than standard posterior techniques. However, the technique possesses its issues, such as unusual positioning, possible plexus-related symptoms, and median segmental lordosis correction. Trying to ease those issues, the idea of a prone transpsoas technique occurred. METHODS: Retrospective, single-centric, comparative, and non-randomized study. The authors paired patients receiving lateral lumbar interbody fusion (LLIF) or prone transpsoas (PTP) to evaluate the technique's impact on the segmental lordosis correction. A correlation test selected the covariates for the matching. p-Values inferior to 0.05 were deemed significant. RESULTS: Seventy-one patients were included in the analysis, 53 in the LLIF group and 18 in the PTP group. The significant covariates to the segmental lordosis correction were technique, preoperative segmental lordosis, cage position, and preoperative pelvic tilt. After the paring model, PTP showed significant segmental lordosis correction potential regarding the LLIF. CONCLUSION: The prone transpsoas approach can significantly enhance the correction of segmental lordosis proportionated to the traditional LLIF approach.

Lateral versus posterior approaches to treat degenerative lumbar pathologies-systematic review and meta-analysis of recent literature.

INTRODUCTION: The lateral lumbar interbody fusion arose as a revolutionary approach to treating several spinal pathologies because the techniques were able to promote indirect decompression and lordosis restoration through a minimally invasive approach allowing for reduced blood loss and early recovery for patients. However, it is still not clear how the technique compares to other established approaches for treating spinal degenerative diseases, such as TLIF, PLIF, and PLF. MATERIAL AND METHODS: This is a systematic review and meta-analysis of articles published in the last 10 years comparing lateral approaches to posterior techniques. The authors included articles that compared the LLIF technique to one or more posterior approaches, treating only degenerative pathologies, and containing at least one of the key outcomes of the study. Exclusion articles that were not original and the ones that the authors could not obtain the full text; also articles without the possibility to calculate the standard deviation or mean were excluded. For count variables, the odds ratio was used, and for continuous variables, the standard means difference (SMD) was used, and the choice between random or fixed-effects model was made depending on the presence or not of significant (p < 0.05) heterogeneity in the sample. RESULTS: Twenty-four articles were included in the quantitative review. As for the intra-/perioperative variables, the lateral approaches showed a significant reduction in blood loss (SMD-1.56, p < 0.001) and similar operative time (SMD = - 0.33, p = 0.24). Moreover, the use of the lateral approaches showed a tendency to lead to reduced hospitalization days (SMD = - 0.15, p = 0.09), with significantly reduced odds ratios of complications (0.53, p = 0.01). As for the clinical outcomes, both approaches showed similar improvement both at improvement as for the last follow-up value, either in ODI or in VAS-BP. Finally, when analyzing the changes in segmental lordosis and lumbar lordosis, the lateral technique promoted significantly higher correction in both outcomes (p < 0.05). CONCLUSION: Lateral approaches can promote significant radiological correction and similar clinical improvement while reducing surgical blood loss and postoperative complications.

Trends in Short Construct Lumbar Fusions Over the Past Decade at a Single Institution.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: (1) To compare the rates of fusion techniques over the last decade; (2) to identify whether surgeon experience affects a surgeon's preferred fusion technique; (3) to evaluate differences in complications, readmissions, mortality, and patient-reported outcomes measures (PROMs) based on fusion technique. SUMMARY OF BACKGROUND DATA: Database studies indicate the number of lumbar fusions have been steadily increasing over the last two decades; however, insufficient granularity exists to detect if surgeons' preferences are altered based on additive surgical experience. METHODS: A retrospective review of continuously collected patients undergoing lumbar fusion at a single urban academic center was performed. Rates of lumbar fusion technique: posterolateral decompression fusion (PLDF), transforaminal lumbar interbody fusion (TLIF), anterior lumbar interbody fusion + PLDF (ALIF), and lateral lumbar interbody fusion + PLDF (LLIF) were recorded. Inpatient complications, 90-day readmission, and inpatient mortality were compared with χ 2 test and Bonferroni correction. The Δ 1-year PROMs were compared with the analysis of variance. RESULTS: Of 3938 lumbar fusions, 1647 (41.8%) were PLDFs, 1356 (34.4%) were TLIFs, 885 (21.7%) were ALIFs, and 80 (2.0%) were lateral lumbar interbody fusions. Lumbar fusion rates increased but interbody fusion rates (2012: 57.3%; 2019: 57.6%) were stable across the study period. Surgeons with <10 years of experience performed more PLDFs and less ALIFs, whereas surgeons with >10 years' experience used ALIFs, TLIFs, and PLDFs at similar rates. Patients were more likely to be discharged home over the course of the decade (2012: 78.4%; 2019: 83.8%, P <0.001). No differences were observed between the techniques in regard to inpatient mortality ( P =0.441) or Δ (postoperative minus preoperative) PROMs. CONCLUSIONS: Preferred lumbar fusion technique varies by surgeon preference, but typically remains stable over the course of a decade. The preferred fusion technique did not correlate with differences in PROMs, inpatient mortality, and patient complication rates. LEVELS OF EVIDENCE: 3-treatment.

Patient-Reported Outcomes Following Anterior and Posterior Surgical Approaches for Multilevel Cervical Myelopathy.

STUDY DESIGN: Retrospective cohort. OBJECTIVE: To compare health-related quality of life (HRQoL) outcomes between approach techniques for the treatment of multilevel degenerative cervical myelopathy (DCM). SUMMARY OF BACKGROUND DATA: Both anterior and posterior approaches for the surgical treatment of cervical myelopathy are successful techniques in the treatment of myelopathy. However, the optimal treatment has yet to be determined, especially for multilevel disease, as the different approaches have separate complication profiles and potentially different impacts on HRQoL metrics. MATERIALS AND METHODS: Retrospective review of a prospectively managed single institution database of patient-reported outcome measures after 3 and 4-level anterior cervical discectomy and fusion (ACDF) and posterior cervical decompression and fusion (PCDF) for DCM. The electronic medical record was reviewed for patient baseline characteristics and surgical outcomes whereas preoperative radiographs were analyzed for baseline cervical lordosis and sagittal balance. Bivariate and multivariate statistical analyses were performed to compare the two groups. RESULTS: We identified 153 patients treated by ACDF and 43 patients treated by PCDF. Patients in the ACDF cohort were younger (60.1 ± 9.8 vs . 65.8 ± 6.9 yr; P < 0.001), had a lower overall comorbidity burden (Charlson Comorbidity Index: 2.25 ± 1.61 vs . 3.07 ± 1.64; P = 0.002), and were more likely to have a 3-level fusion (79.7% vs . 30.2%; P < 0.001), myeloradiculopathy (42.5% vs . 23.3%; P = 0.034), and cervical kyphosis (25.7% vs . 7.69%; P = 0.027). Patients undergoing an ACDF had significantly more improvement in their neck disability index after surgery (-14.28 vs . -3.02; P = 0.001), and this relationship was maintained on multivariate analysis with PCDF being independently associated with a worse neck disability index (+8.83; P = 0.025). Patients undergoing an ACDF also experienced more improvement in visual analog score neck pain after surgery (-2.94 vs . -1.47; P = 0.025) by bivariate analysis. CONCLUSIONS: Our data suggest that patients undergoing an ACDF or PCDF for multilevel DCM have similar outcomes after surgery.

Increased Surgeon-specific Experience and Volume is Correlated With Improved Clinical Outcomes in Lumbar Fusion Patients.

STUDY DESIGN: The present study design was that of a single center, retrospective cohort study to evaluate the influence of surgeon-specific factors on patient functional outcomes at 6 months following lumbar fusion. Retrospective review of a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis identified the present study population. OBJECTIVE: This study seeks to evaluate surgeon-specific variable effects on patient-reported outcomes such as Oswestry Disability Index (ODI) and the effect of North American Spine Society (NASS) concordance on outcomes in the setting of variable surgeon characteristics. SUMMARY OF BACKGROUND DATA: Lumbar fusion is one of the fastest growing procedures performed in the United States. Although the impact of surgeon-specific factors on patient-reported outcomes has been contested, studies examining these effects are limited. METHODS: This is a single center, retrospective cohort study analyzing a prospectively maintained database of patients who underwent neurosurgical lumbar instrumented arthrodesis by 1 of 5 neurosurgery fellowship trained spine surgeons. The primary outcome was improvement of ODI at 6 months postoperative follow-up compared with preoperative ODI. RESULTS: A total of 307 patients were identified for analysis. Overall, 62% of the study population achieved minimum clinically important difference (MCID) in ODI score at 6 months. Years in practice and volume of lumbar fusions were statistically significant independent predictors of MCID ODI on multivariable logistic regression ( P =0.0340 and P =0.0343, respectively). Concordance with evidence-based criteria conferred a 3.16 (95% CI: 1.03, 9.65) times greater odds of achieving MCID. CONCLUSION: This study demonstrates that traditional surgeon-specific variables predicting surgical morbidity such as experience and procedural volume are also predictors of achieving MCID 6 months postoperatively from lumbar fusion. Independent of surgeon factors, however, adhering to evidence-based guidelines can lead to improved outcomes.

[The morbidity of the posterior iliac crest bone graft harvesting could be an overestimated fact. Study in patients with open posterolateral lumbar fusion]. / La morbilidad del sitio donante de injerto de cresta ilíaca posterior podría ser un hecho sobreestimado. Estudio en pacientes con fusión lumbar posterolateral abierta.

INTRODUCTION: spinal fusion is used to treat, among other pathologies, the degenerative intervertebral disc disease. Autologous iliac crest bone grafting is the golden standard treatment for increasing the rate of fusion; however, it isn't free of complications. OBJECTIVES: to investigate whether patients who have posterior iliac crest graft harvesting and are blinded to the donor site, can identify from which side the graft was harvested, and whether the intensity of this pain is related to the amount of graft obtained. MATERIAL AND METHODS: prospective, experimental, randomized and comparative, single-blind study. Adult patients who underwent primary instrumented open posterolateral lumbar fusion with autologous iliac crest bone graft between July 2019 and April 2020 were included. Patients were divided into two randomized groups. The amount of graft to be harvested was according to surgical needs. The patients were asked about pain according to the visual analogue scale in the first, third and sixth months after surgery, always requesting that the most painful side be identified. RESULTS: a total of 44 patients (n = 23 right crest, n = 21 left crest) were analyzed. Most patients were unable to identify the side from which the bone graft was harvested, with a statistically significant difference (p-value 0.0001). CONCLUSION: iliac crest bone graft harvesting is an effective and safe procedure that improves the rates of fusion without increasing the patient's morbidity.

INTRODUCCIÓN: la fusión espinal es utilizada para tratar, entre otras patologías, las enfermedades degenerativas discales. El injerto óseo autólogo de cresta ilíaca es el estándar de oro para aumentar las probabilidades de fusión; sin embargo, no está exento de complicaciones. OBJETIVOS: investigar si los pacientes a los que se les recolecta injerto de cresta ilíaca posterior y son cegados al lado del sitio donante, pueden identificar de qué lado se tomó dicho injerto y si la intensidad de este dolor está en relación con la cantidad de injerto obtenido. MATERIAL Y MÉTODOS: trabajo prospectivo, experimental, aleatorizado y comparativo, simple ciego. Se incluyeron pacientes adultos operados entre Julio de 2019 hasta Abril de 2020, a los cuales se les realizó una cirugía primaria de artrodesis lumbar posterolateral abierta instrumentada, con colocación de injerto óseo autólogo de cresta ilíaca. Se dividió a los pacientes en dos grupos aleatorizados. La cantidad de injerto a recolectar fue de acuerdo a las necesidades quirúrgicas. Se interrogó por el dolor según escala visual analógica al primer, tercer y sexto mes de la cirugía, siempre solicitando que se identifique el lado más doloroso. RESULTADOS: se analizaron 44 pacientes (n = 23 cresta derecha, n = 21 cresta izquierda). La mayoría de los pacientes no lograron identificar el lado del cual se obtuvo el injerto óseo, con una diferencia estadística ampliamente significativa (p = 0.0001). CONCLUSIÓN: la obtención de injerto óseo de cresta ilíaca es un procedimiento efectivo y seguro, que mejora las probabilidades de fusión sin aumentar la morbilidad del paciente.