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.

Are Modic Changes Able to Help Us in Our Clinical Practice? A Study of the Modic Changes in Young Adults During Working Age.

STUDY DESIGN: Modic changes [vertebral endplate spinal changes (VESC)] have been related to degenerative disk disease, and in past decades it was thought that their presence justified the surgical treatment, in particular spinal fusion. OBJECTIVE: The aim of the present study is to investigate its prevalence and features in a population of young workers suffering from low back pain, and explore the eventual relationship with the treatment applied in each case. BACKGROUND DATA: We conducted a retrospectively review of 450 magnetic resonance images from our hospital, in patients with low back pain or sciatica and age below 40. MATERIALS AND METHODS: Age, sex, symptoms predominance, concurrence with other spine disease, VESC type, evolution, level/s of involvement and placement, affected disk location and extent of the disease, disk height, and status of the endplate were recorded. The applied treatment was divided in groups according to the degree of invasiveness of the procedure. RESULTS: Prevalence of VESC was 13.05% predominant in patients over 30 years, and 100% associated to disk degenerative changes. Most frequent features were: type I (54%), lower lumbar region (98%), along with a decreased disk height (68%), and distortion of the disk endplates (98%, P<0.01). The patients with VESC presented a favorable outcome with conservative treatment, but were more frequently associated with invasive treatment, compared with non-VESC patients (P<0.024). CONCLUSIONS: VESC prevalence increases with age, underlying the degenerative causative etiology. Surgical indication should not be stated on the basis of the VESC findings alone, the main factor for indicating surgery depends more on other associated degenerative spinal changes.

[Interspinous spacers and disc herniation. Geomorphometric and clinical study of 71 cases treated by L4-L5 microdiscectomy associated to spacer placement]. / Dispositivos interespinosos y hernia discal. Estudio morfogeométrico y clínico de 71 casos tratados con microdiscectomía L4-L5 asociada a colocación de espaciador.

OBJECTIVE: A controversial indication of interspinous spacers is their use as a complement to discectomy. At the present time, there is no solid clinical evidence of effectiveness of that association, which might result from variability in spacer positioning, restricting its correct biomechanical actions. In this study our goal was to identify and analyse the variability in the placement of an interspinous spacer, and to investigate its relationship with the clinical results. MATERIALS AND METHODS: We performed a retrospective study on X-ray films from 71 patients suffering from disc herniation in L4-L5 who underwent surgery in our hospital, consisting of: microdiscectomy and biomed interspinous spacer implantation. The geomorphometric techniques used to analyse the data were procrustes superimposition and principal components analysis. We compared the clinical results (using the Herron and Turner scale), segmental lordosis and surgical distraction with the geomorphometric parameters. RESULTS: Significant morphological variability was found in the implant position showing cephalo-caudal translation and clockwise-counterclockwise rotations. This variability did not correlate with clinical results. A relationship with anatomical features (lordosis) and additional surgical distraction was identified. A different morphology of implant-segment configuration was identified in cases with recurrence of disc herniation. CONCLUSIONS: Geometric morphometrics allowed identifying high variability in the final placement of interspinous spacers. Nevertheless, it seems not to be related to the clinical outcome, depending rather on the degree of lordosis and distraction. Some differences in segment-implant morphology were identified in cases with recurrences. To assess the effectiveness of spacers, larger studies including morphological and clinical variables are required.

Estudio preliminar de casos y controles de la morfología axial L4-L5 en la hernia de disco / Preliminary case-control study of axial L4- L5 morphology in disc herniation

Una de las cuestiones discutidas es el papel de los factores genéticos y adquiridos en la etiologia de la hernia de disco. Como expresión genómica, el estudio de la morfología podría clarificar dicho papel. Las recientes técnicas de morfometría geométrica (análisis Procrustes generalizado y estudio de componentes principales, entre otras) permiten analizar la forma desde un enfoque no euclidiano, brindando una nueva via de investigación que puede ser aplicada en el raquis. En el presente trabajo empleamos técnicas de morfometría geométrica para analizar la forma axial L4-L5 en pacientes con hernia de disco (n = 69) y controles sanos (n = 87). Se observó una variabilidad de forma a modo de expansión-contracción coronal, a partir del centro del canal medular. Se hallaron diferencias morfológicas entre los controles y las hernias: potenciales factores de riesgo que afectaron principalmente a las láminas y la orientación interapofisaria, condicionando cambios en la morfología del canal. Los resultados apoyan un origen genético de la variabilidad morfológica, con un importante dimorfismo sexual. No obstante, el cambio más relevante para la discriminación la presencia y la ausencia de hernia fue el tamaño del disco, que varió significativamente con el peso. Nuestros hallazgos contribuyen a mejorar el conocimiento morfológico espinal, y a entender el papel de la forma en la hernia de disco, como expresión de la genética, frente a otros factores etiológicos adquiridos. Las técnicas de morfometría geométrica ofrecen una prometedora vía para la investigación de la columna, recomendándose un mayor uso dada la escasez de publicaciones al respecto...