Background: Massive intraoperative blood loss (IBL) is a serious complication in complex spine surgeries such as deformity correction, multilevel fusion, tumor resection, and revision procedures. While no strict definition exists, blood loss exceeding 1500 mL or 20% of estimated blood volume is generally considered clinically significant. Excessive bleeding increases the risk of hemodynamic instability, transfusion-related complications, postoperative infection, and prolonged hospitalization. Methods: This narrative review summarizes the current understanding of the incidence, risk factors, anatomical vulnerabilities, and evidence-based strategies for managing IBL in spine surgery through comprehensive literature analysis of recent studies and clinical guidelines. Results: Key risk factors include patient characteristics (anemia, obesity, advanced age, medication use), surgical variables (multilevel instrumentation, revision status, operative time), and pathological conditions (hypervascular tumors, severe deformity). Perioperative medication management is critical, requiring discontinuation of NSAIDs (5–7 days), antiplatelet agents (5–7 days), and NOACs (48–72 h) preoperatively to minimize bleeding risk. The thoracolumbar junction and hypervascular spinal lesions are especially prone to bleeding due to dense vascular anatomy. Evidence-based management strategies include comprehensive preoperative optimization, intraoperative hemostatic techniques, antifibrinolytic agents, topical hemostatic products, cell salvage technology, and structured transfusion protocols. Conclusions: Effective management of massive IBL requires a multimodal approach combining preoperative risk assessment and medication optimization, intraoperative hemostatic strategies including tranexamic acid administration, advanced monitoring techniques, and coordinated transfusion protocols. Particular attention to perioperative management of anticoagulant and antiplatelet medications is essential for bleeding risk mitigation. Understanding patient-specific risk factors, surgical complexity, and anatomical considerations enables surgeons to implement targeted prevention and management strategies, ultimately improving patient outcomes and reducing complications in high-risk spine surgery procedures.

Proline metabolism has been identified as a significant player in several neoplasms, but knowledge of its role in gliomas is limited despite it providing a promising line of pursuit. Data on proline metabolism in the brain are somewhat historical. This study aims to investigate alterations of proline metabolism in gliomas of WHO grade 4 (GG4) in the context of the brain. A total of 20 pairs of samples were studied, consisting of excised tumor and unaffected brain tissue, obtained when partial brain resection was required to reach deep-seated lesions. Levels of proline oxidase/proline dehydrogenase (POX/PRODH), Δ¹-pyrroline-5-carboxylate reductases (PYCR1/2/3), prolidase (PEPD), and metalloproteinases (MMP-2, MMP-9) were assessed, along with the concentration of proline and proline-related metabolites. In comparison to normal brain tissue, POX/PRODH expression in GG4 was found to be suppressed, while PYCR1 expression and activity of PEPD, MMP-2, and -9 were upregulated. The GG4 proline concentration was 358% higher. Hence, rewiring of the proline metabolism in GG4 was confirmed for the first time, with a low-POX/PRODH/high-PYCR profile. High PEPD and MMPs activity is in keeping with GG4-increased collagen turnover and local aggressiveness. Further studies on the mechanisms of the interplay between altered proline metabolism and the GG4 microenvironment are warranted.

Background: In recent decades, the adoption of minimally invasive (non-endoscopic) cervical techniques has grown significantly. Advancements in surgical instrumentation have broadened the spectrum of available percutaneous interventions, thus providing viable alternative treatment options for patients with prolonged, conservative treatment-resistant ailments due to contained cervical disc herniation. The aim of this study was to perform a systematic review and meta-analysis in order to evaluate the effectiveness and safety of minimally invasive percutaneous (non-endoscopic) cervical techniques. Methods: A comprehensive literature search was conducted using the PubMed, Cochrane Library, and SCOPUS databases up to July 2024, in accordance with the PRISMA guidelines. Outcomes measured included Visual Analogue Scale (VAS) scores, the Neck Disability Index (NDI), and MacNab scores, assessing pain relief and functional recovery. The risk of bias was evaluated using the Cochrane risk of bias tool (RoB 2) and the risk of bias in nonrandomized studies of interventions (ROBINS-I) tool, with statistical analyses conducted in R software (version 4.3.1). Results: Out of 847 records, 21 studies (covering 1580 patients) were included in the final analysis. Five different percutaneous minimally invasive cervical procedures were incorporated into this review: nucleoplasty (n = 973), discectomy (n = 311), a combination of nucleoplasty and discectomy (n = 98), annuloplasty (n = 33), and pulsed radiofrequency (n = 17). The mean patient age was 49.5, with a gender distribution of 47.7% male and 52.3% female. A meta-analysis of six studies on cervical nucleoplasty (400 patients) demonstrated a significant reduction in pain scores, with a standardized mean difference (SMD) of −4.68 (95% CI: −8.77; −0.59, p = 0.032). However, a high heterogeneity (I² = 98.8%, Q = 407.31, p < 0.001) was observed, indicating significant variability across studies. The reoperation rate among patients was 3.4%, with discitis and device-related complications being the most frequently reported adverse events. Conclusions: Minimally invasive percutaneous cervical interventions provide effective pain relief and functional improvement for patients with cervical disc herniation, as evidenced by reductions in VAS scores and positive MacNab outcomes. The choice of the most appropriate technique should be based on individual clinical scenarios, surgeon expertise, and patient preferences, as no single method demonstrates clear superiority according to clinical outcomes or complication rates.

Background: Contained lumbar disc herniation is a prevalent cause of chronic low back pain and functional impairment. The Disc-FX system, a minimally invasive, percutaneous technique integrating nucleotomy, nucleus ablation, and annuloplasty, offers a multimodal approach to managing early degenerative disc disease. Despite promising short-term outcomes, evidence regarding long-term effectiveness remains limited. Methods: This single-center cohort study evaluated 197 patients (median age: 48 years; 56.85% female) who underwent the Disc-FX procedure between 2017 and 2024. Patients were followed for up to 84 months. Pain and disability were assessed using a Visual Analog Scale (VAS) and the Oswestry Disability Index (ODI), respectively, while satisfaction was measured by the MacNab criteria. Multivariable models, including cumulative link models and linear mixed-effects models, were used to identify predictors of outcomes. Results: The Disc-FX procedure resulted in significant and sustained improvements in pain and function. Mean VAS scores decreased from 7.79 preoperatively to 4.31 at 12 months and remained below baseline at 84 months (5.05). ODI scores improved from 15.43 preoperatively to 9.62 at 36 months, rising slightly to 12.75 at 84 months. Good or excellent outcomes were reported in 66.9% of patients according to MacNab criteria. Male sex (OR = 0.41), longer symptom duration (OR = 0.85), and presence of radicular symptoms (OR = 0.39) were significantly associated with less favorable outcomes. Reoperation occurred in 26.4% of cases, predominantly within the first year and most frequently at L4/L5. Complications were rare (3.08%). Conclusions: This study provides robust evidence supporting the long-term clinical efficacy of the Disc-FX procedure in selected patients with contained lumbar disc herniation. While overall outcomes are favorable, optimal results depend on early intervention and careful patient selection, particularly in relation to symptom chronicity and the presence of radicular signs.

We aimed to study brain tissue oxygenation during the period of controlled reduction of arterial blood pressure - a maneuver often used in extended endoscopic skull base surgery for bloodless operative field. Intracranial pressure, arterial blood pressure and the resultant cerebral perfusion pressure were measured during extended endoscopic skull base surgery in 5 patients with diagnosed tumors of the skull base and arterial hypertension. Simultaneously, in those patients, we measured partial pressure of oxygen in the brain parenchyma (PbtO2). Values of PbtO2 lower than 15 mm Hg (risk of brain ischemia) were observed in 3 patients for periods of 40 min, 110 min and 123 min, respectively. In 2 of these patients, no hypotension (mean arterial pressure <65 mm Hg) was necessary for bloodless operative field. Another 2 patients had PbtO2 above 30 mm Hg at the time when their mean arterial pressure was below 65 mm Hg. The time course of PbtO2 followed that of cerebral perfusion pressure with a time lag of 40-60 s in all patients. Moderate reduction of arterial pressure, often used to obtain bloodless operative field during extended endoscopic skull base surgery, may in patients with the medical history of arterial hypertension be associated with critically low values of partial oxygen pressure in brain tissue.