Revisión sistemática de las aplicaciones y límites de la impresión 3D en la cirugía de raquis / Systematic review of the utility and limits of 3D printing in spine surgery

Objetivo: El objetivo principal de este estudio ha sido demostrar por qué la impresión aditiva permite hacer más visibles y entendibles los procesos patológicos quirúrgicos complejos que afectan al raquis, aumentando la precisión, la seguridad y la fiabilidad del procedimiento quirúrgico.MetodologíaSe realizó una revisión sistemática de los trabajos publicados en los últimos 10 años, sobre la cirugía de raquis asistida por impresión 3D, de acuerdo con la declaración PRISMA 2020. Con las palabras clave «printing 3D» y «spine surgery» se hicieron búsquedas en las bases de datos Pubmed, Embase, Cochrane Database of Systematic Reviews, Google Scholar y Opengrey, que se completó con la búsqueda manual a través de la lista de referencias bibliográficas de los artículos que fueron seleccionados siguiendo los criterios de inclusión y exclusión definidos.ResultadosDel análisis de los 38 estudios seleccionados resultó que la impresión 3D es útil en la planificación quirúrgica, en la enseñanza médica, en la relación médico-paciente, así como en el diseño de plantillas de navegación e implantes de raquis y, en investigación, ofreciendo un magnífico apoyo al proceder quirúrgico.ConclusionesEl uso de biomodelos impresos de forma tridimensional permite: hacer más visibles y entendibles los procesos patológicos quirúrgicos complejos que afectan al raquis; aumentar la exactitud, precisión y seguridad del procedimiento quirúrgico; y abrir la posibilidad de poner en práctica tratamientos personalizados, fundamentalmente en la cirugía tumoral. (AU)

Objective: The main objective of this study has been to demonstrate why additive printing allows to make complex surgical pathological processes that affect the spine more visible and understandable, increasing precision, safety and reliability of the surgical procedure.MethodsA systematic review of the articles published in the last 10 years on 3D printing-assisted spinal surgery was carried out, in accordance with PRISMA 2020 declaration. Keywords «3D printing» and «spine surgery» were searched in Pubmed, Embase, Cochrane Database of Systematic Reviews, Google Scholar and Opengrey databases, which was completed with a manual search through the list of bibliographic references of the articles that were selected following the defined inclusion and exclusion criteria.ResultsFrom the analysis of the 38 selected studies, it results that 3D printing is useful in surgical planning, medical teaching, doctor–patient relationship, design of navigation templates and spinal implants, and research, optimizing the surgical process by focusing on the patient, offering magnificent support during the surgical procedure.ConclusionsThe use of three-dimensional printing biomodels allows: making complex surgical pathological processes that affect the spine more visible and understandable; increase the accuracy, precision and safety of the surgical procedure, and open up the possibility of implementing personalized treatments, mainly in tumor surgery. (AU)

Systematic review of the utility and limits of 3D printing in spine surgery.

OBJECTIVE: The main objective of this study has been to demonstrate why additive printing allows to make complex surgical pathological processes that affect the spine more visible and understandable, increasing precision, safety and reliability of the surgical procedure. METHODS: A systematic review of the articles published in the last 10 years on 3D printing-assisted spinal surgery was carried out, in accordance with PRISMA 2020 declaration. Keywords "3D printing" and "spine surgery" were searched in Pubmed, Embase, Cochrane Database of Systematic Reviews, Google Scholar and Opengrey databases, which was completed with a manual search through the list of bibliographic references of the articles that were selected following the defined inclusion and exclusion criteria. RESULTS: From the analysis of the 38 selected studies, it results that 3D printing is useful in surgical planning, medical teaching, doctor-patient relationship, design of navigation templates and spinal implants, and research, optimizing the surgical process by focusing on the patient, offering magnificent support during the surgical procedure. CONCLUSIONS: The use of three-dimensional printing biomodels allows: making complex surgical pathological processes that affect the spine more visible and understandable; increase the accuracy, precision and safety of the surgical procedure, and open up the possibility of implementing personalized treatments, mainly in tumor surgery.

Frontotemporal disorders: the expansive panoply of syndromes and spectrum of etiologies.

Background: Frontotemporal lobe disorders (FTD) are amongst the most common brain neurodegenerative disorders. Their relatively covert, frequently subtle presentations and diverse etiologies, pose major challenges in diagnosis and treatments. Recent studies have yielded insights that the etiology in the majority are due to environmental and sporadic causes, rather than genetic in origin. Aims: To retrospectively examine the cognitive and behavioral impairments in the veteran population to garner the range of differing syndrome presentations and etiological subcategories with a specific focus on frontotemporal lobe disorders. Methodology: The design is a retrospective, observational registry, case series with the collection of epidemiological, clinical, cognitive, laboratory and radiological data on people with cognitive and behavioral disorders. Inclusion criteria for entry were veterans evaluated exclusively at Orlando VA Healthcare System, neurology section, receiving a diagnosis of FTD by standard criteria, during the observation period dated from July 2016 to March 2021. Frontotemporal disorders (FTD) were delineated into five clinical 5 subtypes. Demographic, cardiovascular risk factors, cognitive, behavioral neurological, neuroimaging data and presumed etiological categories, were collected for those with a diagnosis of frontotemporal disorder. Results: Of the 200 patients with FTD, further cognitive, behavioral neurological evaluation with standardized, metric testing was possible in 105 patients. Analysis of the etiological groups revealed significantly different younger age of the traumatic brain injury (TBI) and Gulf War Illness (GWI) veterans who also had higher Montreal Cognitive Assessment (MOCA) scores. The TBI group also had significantly more abnormalities of hypometabolism, noted on the PET brain scans. Behavioral neurological testing was notable for the findings that once a frontotemporal disorder had been diagnosed, the four different etiological groups consistently had abnormal FRSBE scores for the 3 principal frontal presentations of (i) abulia/apathy, (ii) disinhibition, and (iii) executive dysfunction as well as abnormal Frontal Behavioral Inventory (FBI) scores with no significant difference amongst the etiological groups. The most common sub-syndromes associated with frontotemporal syndromes were the Geschwind-Gastaut syndrome (GGS), Klüver-Bucy syndrome (KBS), involuntary emotional expression disorder (IEED), cerebellar cognitive affective syndrome (CCA), traumatic encephalopathy syndrome (TES) and prosopagnosia. Comparisons with the three principal frontal lobe syndrome clusters (abulia, disinhibition, executive dysfunction) revealed a significant association with abnormal disinhibition FRSBE T-scores with the GGS. The regression analysis supported the potential contribution of disinhibition behavior that related to this complex, relatively common behavioral syndrome in this series. The less common subsyndromes in particular, were notable, as they constituted the initial overriding, presenting symptoms and syndromes characterized into 16 separate conditions. Conclusion: By deconstructing FTD into the multiple sub-syndromes and differing etiologies, this study may provide foundational insights, enabling a more targeted precision medicine approach for future studies, both in treating the sub-syndromes as well as the underlying etiological process.

Spinal health in 40 patients in the initial stage of laboural life. Morfogeometric, biological and environmental study.

INTRODUCTION: Assuming that spinal shape is a genetic expression, its analysis and acquired factors could assess their respective contribution to early spine deterioration. MATERIAL AND METHODS: A geometric morphometric analysis was retrospectively performed on sagittal lumbar MRI of young patients with back pain to identify lumbar spine shape changes. Using Geometric Morphometrics, findings were analyzed with anthropometric, radiological, and clinical variables. RESULTS: 80 cases under 26 years of age were collected, 55 men (mean age 22.81) and 25 women (mean age 23.24). MRI abnormalities were reported in 57.5%: single altered disc (N=17), root compromises (N=8), and transition anomalies (35%).In the non-normal MRI subgroup, shape variation included: increased lordosis, enlarged vertebral body, canal stenosis, and lumbarization of S1. In non-Spanish origin patients, lumbar straightening and segmental deformities were prevalent. Morphometrics findings showed that lumbosacral transition anomalies are frequently underreported. CONCLUSIONS: Genetic factors could be the main determinants of abnormality in MRIs under 26 years. The primary markers are transitional abnormalities, segmental deformities, and canal stenosis. In foreign populations, shape changes could suggest spine overload at an early age.

Superlative Artistic Abilities in a Patient With Post-traumatic Brain Injury.

This case describes a patient who exhibits newfound superlative abilities in painting, music, philosophy, culinary, and performing arts after a traumatic brain injury (TBI) involving the frontal and temporal lobes. Such a dramatic change in de novo artistic behavior after brain injury is rare but has been reported in other patients with frontotemporal dementia, as well as other neurological diseases. Previous studies have shown that mild frontal cortical dysfunction likely plays a role in facilitating creative endeavors and that artistic circuitry is distributed throughout the brain. The neuronal reorganization which occurs after injuries enhances synapse formation and neural plasticity, which may contribute to the acceleration of artistic output after brain injury. This is likely an underdiagnosed phenomenon and a deeper understanding is required to allow clinicians to more effectively recognize and nurture newfound creativity in the setting of brain damage.

Genetic rhabdomyolysis within the spectrum of the Spinocerebellar Ataxia type 2 responsive to pregabalin.

BACKGROUND: Spinocerebellar Ataxia type 2 is a slowly progressive adult onset ataxia with a broad clinical presentation. CASE PRESENTATION: We describe a man with Spinocerebellar Ataxia type 2 with chronic, severe, and recurrent rhabdomyolysis, as part of the cerebellar ataxia genetic spectrum. Initially rhabdomyolysis was refractory to multiple medications, but entirely resolved and remained in chronic remission with pregabalin. CONCLUSIONS: This is the first report of Spinocerebellar Ataxia type 2 associated with chronic, severe, recurrent rhabdomyolysis as part of its genetic phenotype responsive to pregabalin.

Hemisensory loss in myasthenia gravis.

A 73-year-old white man presents with left-sided ptosis and diplopia in the absence of ophthalmoplegia, with left hemibody paresthesia. He reports intermittent dysphagia and dizziness for 1 month and diarrhoea for 2 months. Serum and electrodiagnostic studies confirmed the diagnosis of myasthenia gravis. This case highlights the non-classic presentation of myasthenia gravis in the absence of ophthalmoplegia with a unique unexplained hemisensory deficit.

Exploding Head Syndrome as Aura of Migraine with Brainstem Aura: A Case Report.

This article reports a case of exploding head syndrome (EHS) as an aura of migraine with brainstem aura (MBA). A middle-aged man presented with intermittent episodes of a brief sensation of explosion in the head, visual flashing, vertigo, hearing loss, tinnitus, confusion, ataxia, dysarthria, and bilateral visual impairment followed by migraine headache. The condition was diagnosed as MBA. Explosive head sensation, sensory phenomena, and headaches improved over time with nortriptyline. This case shows that EHS can present as a primary aura symptom in patients with MBA.

Body Mass Index and sagittal lumbar balance. A geometric morphometrics approach

Geometric Morphometrics (GM) offers a new and interactive way for shape analysis, rarely used in spine morphology study. We used GM to investigate the relationships between being overweight and lumbar sagittal configuration. Age, sex, weight, height and BMI of 152 consecutive spine MRI were retrospectively collected. 66 landmarks were digitized on each midsagittal T2-weighted images. Procrustes superimpositions, Principal Component analysis (PCA), Canonical Variate analysis (CVA), and other multivariate techniques were used to find mean shape consensus and possible shape-BMI covariations. A strong correlation between sagittal lumbar shape and BMI was found. Morphological changes such as telescoping, lordosis and variations in vertebral-disk shape were found to be related with BMI, as well as other common variables such as sex and age. GM helps understand the way in which being overweight influences the lumbar shape. These techniques offer a powerful, reproducible and dynamically interactive method to explore spine shape, with diagnostic, therapeutic and preventive implications. A more extensive use of Geometric Morphometrics in spine shape investigation is proposed

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Permanent Cerebellar Degeneration After Acute Hyperthermia with Non-toxic Lithium Levels: a Case Report and Review of Literature.

This was a study of a 33-year-old man with bipolar disorder treated with lithium who developed cerebellar atrophy after an event of extreme hyperthermia. Unlike previously reported cases of acute cerebellar atrophy after heat stroke, neuroleptic syndrome or lithium toxicity, this case was characterized by a chronic cerebellar atrophy that developed after sepsis-induced hyperthermia in the setting of non-toxic lithium levels. Unique to this case also was the early finding of cerebellar atrophy on MRI 2 weeks after the episode of hyperthermia, long-term neurotoxicity after the novo lithium therapy, and longest follow-up case of chronic cerebellar syndrome after hyperthermia with non-toxic lithium levels.

Intravitreal Injection-Induced Migraine Headaches.

A case of migraine headache triggered by intravitreal injection, and aborted by retrobulbar injection, is reported. To date, migraine and related cephalgia have not been reported after intravitreal injection. Ophthalmologists and neurologists should be aware of this potential sequela of a very common procedure.

Chronic inhibitory effect of riluzole on trophic factor production.

Riluzole is the only FDA approved drug for the treatment of amyotrophic lateral sclerosis (ALS). However, the drug affords moderate protection to ALS patients, extending life for a few months by a mechanism that remains controversial. In the presence of riluzole, astrocytes increase the production of factors protective to motor neurons. The stimulation of trophic factor production by motor neuron associated cells may contribute to riluzole's protective effect in ALS. Here, we investigated the effects of media conditioned by astrocytes and Schwann cells acutely or chronically incubated with riluzole on trophic factor-deprived motor neuron survival. While acute riluzole incubation induced CT-1 secretion by astrocytes and Schwann cells, chronic treatment stimulated a significant decrease in trophic factor production compared to untreated cultures. Accordingly, conditioned media from astrocytes and Schwann cells acutely treated with riluzole protected motor neurons from trophic factor deprivation-induced cell death. Motor neuron protection was prevented by incubation with CT-1 neutralizing antibodies. In contrast, conditioned media from astrocytes and Schwann cells chronically treated with riluzole was not protective. Acute and chronic treatment of mice with riluzole showed opposite effects on trophic factor production in spinal cord, sciatic nerve and brain. There was an increase in the production of CT-1 and GDNF in the spinal cord and CT-1 in the sciatic nerve during the first days of treatment with riluzole, but the levels dropped significantly after chronic treatment with the drug. Similar results were observed in brain for CT-1 and BDNF while there was no change in GDNF levels after riluzole treatment. Our results reveal that riluzole regulates long-lasting processes involving protein synthesis, which may be relevant for riluzole therapeutic effects. Changing the regimen of riluzole administration to favor the acute effect of the drug on trophic factor production by discontinuous long-term treatment may improve the outcome of ALS patient therapy.

Cerebral blood flow changes in depressed patients after treatment with repetitive transcranial magnetic stimulation: evidence of individual variability.

OBJECTIVE: To elucidate the neural mechanisms of depression. BACKGROUND: Despite extensive study, the neurophysiology of the brain's state(s) corresponding to depression remains uncertain. METHODS: HMPAO single photon emission computed tomographic (SPECT) scans were obtained from eight adults diagnosed with major depression resistant to medication (average age 51 years; 4 men) before and immediately after 10 days of 20 Hz repetitive transcranial magnetic stimulation (rTMS) (2000 stimuli/daily 30' treatment). To maximize the likelihood that SPECT scans reflected the state of depression, rather than uncontrolled responses of patients to poorly constrained environments, HMPAO was administered while subjects performed a simple task involving continuous monitoring of the direction of a large arrow on a computer screen and continuously tapping with the left or right index finger according to the direction of the arrow. Mean baseline Beck Depression Inventory (BDI) score was 27.4 (SD = 8.3) and mean posttreatment BDI score was 17.5 (SD = 8.5). RESULTS: Treatment responders (defined by reduction in BDI score of > or = 30%) had significantly less pretreatment blood flow in the left amygdala compared with nonresponders. Responders demonstrated two patterns of change in regional blood flow with treatment: a reduction in orbitofrontal blood flow and/or a reduction in anterior cingulate blood flow. Nonresponders did not demonstrate any regional changes in blood flow with treatment. CONCLUSIONS: These results suggest that there may be either more than one state of depression, or that depression may be associated with more than one pattern of psychologic activity, which in turn defines the depressive experience for individual patients.

Immobilization dystonia.

The mechanisms underlying dystonia after injury are unclear. Pain has been implicated as an important factor. We report four patients who exhibited segmental dystonia following removal of a cast, only two of whom experienced pain during casting. Recent work implicates the cerebral cortex as an important site of neural plasticity underlying the development of dystonia. Cortical changes may be induced by peripheral stimuli that are repetitive, spatially and temporally proximate, stereotyped, and attended. Immobilization by casting may meet these requirements if there is sufficiently persistent sensation of the immobilized limb to assure that it is regularly attended. The fact that all of our patients were immobilized but only two experienced pain during casting suggests that pain is not necessary and immobilization alone may be sufficient for the development of segmental dystonia after peripheral injury, consistent with the implications of animal studies.

Corticosteroid treatment of mitochondrial encephalomyopathies.

BACKGROUND: Mitochondrial encephalopathy with lactic acidosis and stroke-like symptoms (MELAS) is a multisystem disorder characterized by stroke-like episodes, seizures, dementia, headaches,evidence of mitochondrial myopathy. Lactic acidosis and ragged red fibers are often present. A variety of therapies have been used with inconclusive and disappointing results. There have been very few cases of MELAS reported as corticosteroid responsive. SUMMARY: A 27-year-old healthy man was hospitalized with recurrent generalized tonic-clonic seizures, intractable headaches, and stroke-like symptoms. These symptoms improved after the initiation of corticosteroid treatment. Multiple attempts to taper corticosteroids were followed by clinical relapse. Genetic testing in this patient revealed a point mutation at nt 3243 of the mitochondrial tRNA gene, confirming the diagnosis of MELAS. The patient died 1 year later after an episode of status epilepticus. Corticosteroid therapy in individual MELAS patients has been associated with clinical improvement. Discrepancy exists with regard to corticosteroid type, dose, route of administration, length of therapy, patient population, and clinical and metabolic parameters to follow during corticosteroid therapy. CONCLUSIONS: Corticosteroid therapy may be beneficial during acute exacerbation of MELAS.