A Novel Marking Technique for Accurate Minimal Invasive Approaches in Spine Tumor Surgeries With Activated Carbon Marking.

BACKGROUND AND OBJECTIVES: To describe a novel, practical, reproducible, and effective preoperative marking technique for accurate localization of the spinal level in a series of patients with tumor lesions. METHODS: We retrospectively analyzed patients undergoing minimally invasive (MIS) surgery for spine tumors from 2016 to 2021, in which this marking technique was used. Twenty-one patients, with tumor lesions involving difficult radioscopic visualization (cervicothoracic junction or upper dorsal spine, C6-T8), were included. Tumor lesion level was previously determined with enhanced MRI in all cases. Twenty-four to forty-eight hours before surgery, computed tomography image-guided carbon marking was performed by administration of aqueous suspension of carbon with a 21-gauge needle placed resembling the MIS approach planned trajectory. During surgery, activated carbon marking was followed until reaching the final target on the bone. Next, sequential dilators and an MIS retractor were placed. Then, bone resection and tumor exeresis were performed according to the case. RESULTS: Average age was 60.6 years (26-76 years). Fifteen (71%) patients were women. In most cases (76%), tumor pathology involved intradural lesions (meningiomas and schwannomas). In all cases, the marking described allowed to accurately guide the MIS approach to tumor site. Neither intraoperative fluoroscopy nor approach enlargement was required in any procedure. Postoperative complications were reported in only 4 patients, none related with the marking. CONCLUSION: Computed tomography image-guided activated carbon marking allows to accurately lead MIS approaches in a practical, reproducible, and effective way in cases of tumors localized in regions of the spine of difficult radioscopic visualization.

Does Minimally Invasive Hemilaminectomy for Intradural Extramedullary Tumor Resection Prevent Postlaminectomy Kyphosis or Lordosis Loss?

BACKGROUND: Minimally invasive hemilaminectomy is a safe and effective alternative to open laminectomy for treating intradural extramedullary tumors. There are no reports of postoperative kyphosis after this approach. This study aims to determine whether performing minimally invasive spine surgery hemilaminectomy for intradural extramedullary tumors can prevent the development of postlaminectomy kyphosis (PLK) or lordosis loss. MATERIAL AND METHODS: Sixty-five patients with spinal intradural extramedullary tumors who underwent minimally invasive hemilaminectomy surgery and complete pre and postoperative radiologic imaging were included. The effect of the surgical approach on the spinal sagittal axis was assessed by comparing pre- versus postoperative segmental and local Cobb angles at different spinal levels, considering anatomical localization (cervical, thoracic, lumbar, and transition segments) and functional features (mobile, semi-rigid, and transition segments), as well as the extent of the surgical approach (1, 2, or 3 levels) and follow-up. RESULTS: None of the patients had an increase in thoracic kyphosis nor a loss of cervical or lumbar lordosis greater than or equal to 10° after undergoing the minimally invasive spine surgery hemilaminectomy approach. More than 5° of increase in kyphosis was detected on 7.4% and 11.1%, for the segmental and the local angles, respectively; meanwhile, for patients with loss of lordosis, this deviation was detected in 5.3%, for both angles. The occurrence of PLK was more common than that of lordosis loss, but mainly manifested in postoperative angle impairment of less than 5°. No significant differences were evidenced, considering the approach length. CONCLUSIONS: Hemilaminectomy represents a promising approach for preventing PLK and postlaminectomy lordosis loss following intradural extramedullary tumor resection.

Understanding the Landscape of Spinal Injections: Insights and Challenges from Latin America.

BACKGROUND: Low back pain and neck pain are primary causes of disability, with low back pain being a frequent reason for medical consultations. After conservative and pharmacological treatments, spinal injections are considered the next option. Despite multiple guidelines, spinal blocks remain controversial in terms of indication, technique, and operator, leading to considerable interinstitutional variability. The absence of regional studies in Latin America on how spinal surgeons handle spinal injections prompts the objectives of this study: to evaluate spinal surgeons' knowledge and experience, analyze techniques, and identify barriers and challenges in implementing spinal injections, including resource limitations, technology access, and training. METHODS: A cross-sectional survey was performed using a questionnaire specifically designed by the authors. RESULTS: Two hundred sixty spinal surgeons from Latin America participated and answered a 17-question questionnaire; 75% performed their own spinal blocks and they are willing to keep on learning new techniques on the field. The most frequent block, was the lumbar facet injection (80%). And the great majority (76%) used fluoroscopy in their practice. CONCLUSIONS: The study addresses a critical gap in the literature by focusing on spinal interventions in Latin America, where there is a notable lack of regional studies. The majority of the surgeons enrolled perform their own spinal injections, and they are interested in keep on learning. The findings not only contribute to the global discourse on spinal care but also offer a basis for the development of region-specific guidelines and educational initiatives.

Artificial Intelligence Assistance for the Measurement of Full Alignment Parameters in Whole-Spine Lateral Radiographs.

BACKGROUND: Measuring spinal alignment with radiological parameters is essential in patients with spinal conditions likely to be treated surgically. These evaluations are not usually included in the radiological report. As a result, spinal surgeons commonly perform the measurement, which is time-consuming and subject to errors. We aim to develop a fully automated artificial intelligence (AI) tool to assist in measuring alignment parameters in whole-spine lateral radiograph (WSL X-rays). METHODS: We developed a tool called Vertebrai that automatically calculates the global spinal parameters (GSPs): Pelvic incidence, sacral slope, pelvic tilt, L1-L4 angle, L4-S1 lumbo-pelvic angle, T1 pelvic angle, sagittal vertical axis, cervical lordosis, C1-C2 lordosis, lumbar lordosis, mid-thoracic kyphosis, proximal thoracic kyphosis, global thoracic kyphosis, T1 slope, C2-C7 plummet, spino-sacral angle, C7 tilt, global tilt, spinopelvic tilt, and hip odontoid axis. We assessed human-AI interaction instead of AI performance alone. We compared the time to measure GSP and inter-rater agreement with and without AI assistance. Two institutional datasets were created with 2267 multilabel images for classification and 784 WSL X-rays with reference standard landmark labeled by spinal surgeons. RESULTS: Vertebrai significantly reduced the measurement time comparing spine surgeons with AI assistance and the AI algorithm alone, without human intervention (3 minutes vs. 0.26 minutes; P < 0.05). Vertebrai achieved an average accuracy of 83% in detecting abnormal alignment values, with the sacral slope parameter exhibiting the lowest accuracy at 61.5% and spinopelvic tilt demonstrating the highest accuracy at 100%. Intraclass correlation analysis revealed a high level of correlation and consistency in the global alignment parameters. CONCLUSIONS: Vertebrai's measurements can accurately detect alignment parameters, making it a promising tool for measuring GSP automatically.

Navigating the Indeterminate Zone: Surgeons' Decision-Making Factors in Treating Vertebral Metastases with Spinal Instability Scores of 7-12.

BACKGROUND: The Spinal Instability Neoplastic Score (SINS) classification system is a validated and the most widely accepted instrument for defining instability in vertebral metastasis (VM), in which lesions scoring between 7 and 12 are defined as indeterminate and the treatment is controversial. This study aimed to determine which variables more frequently are considered by spine surgeons for choosing between the conservative and the surgical treatment of VMs among patients with an indeterminate SINS. METHODS: A single-round online survey was conducted with 10 spine surgeons with expertise in the management of VMs from our AO Spine Region. In this survey, each surgeon independently reviewed demographic and cancer-related variables of 36 real-life cases of patients with vertebral metastases scored between 7 and 12 in the SINS. Bivariate and multivariate analyses were performed to identify significant SINS and non-SINS variables influencing the decision-making on surgical treatment. RESULTS: The most commonly variables considered important were the SINS element "mechanical pain", rated important for 44.4% of the cases, "lesion type" for 36.1%, and "degree of vertebral collapse" and the non-SINS factor "tumor histology" rated for 13.9% of cases. By far the factor most commonly rated unimportant was "posterior element compromise" (in 72.2% of cases). CONCLUSIONS: Surgeons relied on mechanical pain and type of metastatic lesion for treatment choices. Vertebral collapse, spinal malalignment, and mobility were less influential. Spinal mobility was a predictor of surgical versus non-surgical treatment. The only variables not identified either by surgeons themselves or as a predictor of surgery selection was the presence/degree of posterolateral/posterior element involvement.

Minimally Invasive Approaches for Lumbosacral Plexus Schwannomas.

BACKGROUND AND OBJECTIVES: Lumbosacral plexus schwannomas (LSPSs) are benign, slow-growing tumors that arise from the myelin sheath of the lumbar or sacral plexus nerves. Surgery is the treatment of choice for symptomatic LSPSs. Conventional retroperitoneal or transabdominal approaches provide wide exposure of the lesion but are often associated with complications in the abdominal wall, lumbar or sacral plexus, ureter, and intraperitoneal organs. Advances in technology and minimally invasive (MIS) techniques have provided alternative approaches with reliable efficacy compared with traditional open surgery. We describe 3 MIS approaches using tubular retractor systems according to the lesion level. METHODS: This was a multicenter, retrospective observational cohort study to evaluate the use of MIS tubular approaches for surgical resection of LSPSs. We included 23 lumbar and upper sacral plexus schwannomas. Clinical presentation, spinal level, surgical duration, degree of resection, days of hospitalization, pathological anatomy of the tumor, approach-related surgical difficulties, and outcomes were collected. RESULTS: The posterior oblique approach was used in 43.5% of the cases, the transpsoas approach in 39.1%, and the transiliac in 17.4%. The mean operative time was 3.3 hours, and the mean hospitalization was 2.5 days. All tumors were WHO grade 1 schwannoma. Postoperative MRI confirms gross total resection in 91.3% of the patients. No patient requires instrumentation. The pros and cons of each approach were summarized. CONCLUSION: The MIS approaches adapted to the lumbar level may improve surgeons' comfort allowing a safe resection of retroperitoneal LSPS.

Measuring the Delay in the Referral of Unstable Vertebral Metastasis to the Spine Surgeon: A Retrospective Study in a Latin American Institution.

Background: The delay in the referral of patients with potential surgical vertebral metastasis (VM) to the spine surgeon is strongly associated with a worse outcome. The spinal instability neoplastic score (SINS) allows for determining the risk of instability of a spine segment with VM; however, it is almost exclusively used by specialists or residents in neurosurgery or orthopedics. The objective of this work is to report the delay in surgical consultation of patients with potentially unstable and unstable VM (SINS >6) at our center. Material: We performed a 5-year single-center retrospective analysis of patients with spine metastasis on computed tomography (CT). Patients were divided into Group 1 (G1), potentially unstable VM (SINS 7-12), and Group 2 (G2), unstable VM (SINS 13-18). Time to surgical referral was calculated as the number of days between the report of the VM in the CT and the first clinical assessment of a spinal surgeon on the medical records. Results: We analyzed 220 CT scans, and 98 met the selection criteria. Group 1 had 85 patients (86.7%) and Group 2 had 13 (13.3%). We observed a mean time to referral of 83.5 days in the entire cohort (std = 127.6); 87.6 days (std = 135.1) for G1, and 57.2 days (std = 53.8) for G2. The delay in referral showed no significant correlation with the SINS score. Conclusion: We report a mean delay of 83.5 days in the surgical referral of VM (SINS >6, n = 98). Both groups showed cases of serious referral delay, with 25% of patients having the first surgical consultation more than three months after the CT study.

Carbon-Assisted Minimally Invasive Transtubular Approach for Intercostal Nerve Schwannoma.

BACKGROUND AND OBJECTIVES: The intraoperative localization of an intercostal nerve schwannoma (INS) is extremely difficult because the lesion is generally not palpable, and the fluoroscopic visualization of anatomic landmarks in the ribs is unsatisfactory. Using activated carbon suspension to mark the soft-tissue approach could improve INS localization. We present a novel, simple, reproducible carbon-assisted minimally invasive transtubular approach for an INS. METHODS: The patient was a 57-year-old man with a painful 12th left INS arising below the floating rib. A computed tomography image-guided, tumor-to-skin marking with aqueous carbon suspension was performed 48 hours before surgery. A minimally invasive transtubular approach following the carbon path allowed a precise tumor location. RESULTS: The INS was completely removed. The patient's thoracic radicular pain was immediately relieved after surgery. He was discharged the following day with residual numbness on the left thoracic side. At the 5-year follow-up, no tumor recurrence was noted in the control MRI. CONCLUSION: This article presents an alternative novel technique for resecting an intercostal schwannoma. Using a transtubular approach with carbon-marking assistance allowed a tumor gross total resection with immediate pain relief and a successful outcome.

Rara presentación de un linfoma espinal: informe de caso y diagnóstico mediante resonancia magnética / Rare presentation of a spinal lymphoma: case report and diagnosis by magnetic resonance imaging

El linfoma primario del sistema nervioso central es una forma de enfermedad extraganglionar originada en el cerebro, la leptomeninges, la médula espinal o los ojos. Los tumores espinales son neoplasias de baja prevalencia y pueden causar una morbimortalidad neurológica considerable. El linfoma aislado que surge dentro del conducto dural es la forma menos común de linfoma primario del sistema nervioso central: representa aproximadamente el 1% de los casos y se observa más a menudo en el contexto de diseminación secundaria que como el sitio primario de origen. Los síntomas son inespecíficos y dependen del nivel espinal involucrado. La presentación es insidiosa e incluye dorsalgia, debilidad y dificultad progresiva para la deambulación. La resonancia magnética es la modalidad de elección para búsqueda de lesiones dentro del conducto espinal/raquídeo, en pacientes que presentan síntomas neurológicos. El tratamiento quirúrgico no resulta útil, y el objetivo principal de la cirugía es conocer el diagnóstico histológico. (AU)

A primary central nervous system lymphoma is a form of extranodal disease originating in the brain, leptomeninges, spinal cord, or eyes. Spinal tumors are low-prevalence neoplasms and can cause considerable neurological morbidity and mortality. An isolated lymphoma emerging within the dural canal is the rarest form of primary central nervous system lymphoma: it accounts for approximately 1% of cases occurring more often in the context of secondary dissemination than as the primary site of origin. Symptoms are nonspecific and depend on the spinal level involved. The presentation is insidious and includes dorsalgia, weakness, and progressive difficulty in ambulatory function. MRI is the modality of choice to search for lesions within the spinal/rachial canal in patients presenting with neurological symptoms. Surgical treatment is not helpful, and the main objective of surgery is to know the histological diagnosis. (AU)

Reversible focal intracranial hypertension swine model with continuous multimodal neuromonitoring.

BACKGROUND: Intracranial hypertension (HI) is associated with worse neurological outcomes and higher mortality. Although there are several experimental models of HI, in this article we present a reproducible, reversible, and reliable model of intracranial hypertension, with continuous multimodal monitoring. NEW METHOD: A reversible intracranial hypertension model in swine with multimodal monitoring including intracranial pressure, arterial blood pressure, heart rate variation, brain tissue oxygenation, and electroencephalogram is developed to understand the relationship of ICP and EEG. By inflating and deflating a balloon, located 20 mm anterior to the coronal suture and a 15 mm sagittal suture, we generate intracranial hypertension events and simultaneously measure intracranial pressure and oxygenation in the contralateral hemisphere and the EEG, simulating the usual configuration in humans. RESULTS: We completed 5 experiments and in all of them, we were able to complete at least 6 events of intracranial hypertension in a stable and safe way. For events of 20-40 mmHg of ICP we need an median (IQR) of 4.2 (3.64) ml of saline solution into the Foley balloon, a median (IQR) infusion time of 226 (185) second in each event and for events of 40-50 mmHg of ICP we need a median (IQR) of 5.1 (4.66) ml of saline solution, a median (IQR) infusion time of 280 (48) seconds and a median (IQR). The median (IQR) maintenance time was 352 (77) seconds and 392 (166) seconds for 20-40 mmHg and 40-50 mmHg of ICP, respectively. COMPARISON WITH EXISTING METHOD(S): Existing methods do not include EEG measures and do not present the reversibility of intracranial hypertension. CONCLUSIONS: Our model is fully reproducible, it is capable of generating reversible focal intracranial hypertension through strict control of the injected volume, it is possible to generate different infusion rates of the volume in the balloon, in order to generate different scenarios, the data obtained are sufficient to determine the brain complacency in real time. and useful for understanding the pathophysiology of ICP and the relationship between ICP (CPP) and EEG.