Long term outcome and fusion rate of transdiscal fixation for L5-S1 high grade spondylolisthesis.

OBJECTIVE: High grade spondylolisthesis (HGS) is a quite rare entity and many techniques are available to address this condition. In 1994 Abdu et al. proposed a transdiscal fixation approach that achieved a good clinical outcome. We analyse outcome and fusion achieved in patients treated by transdiscal fixation after 1-year follow-up. METHODS: We reviewed patients operated through transdiscal fixation since 2014 with a follow-up of at least 1 year, and compared preoperative and postoperative clinical measures (ODI, VAS and EQ-5D) and postoperative complications. Also, we analyzed the degree of fusion on CT scan with Lenke and Birdwell criteria. RESULTS: Twelve patients were included in the study with a mean follow-up of 49.4 months (range 12.8-84.1 months). Three cases presented a Meyerding grade IV spondylolisthesis and 9 cases grade III. At 1-year follow-up mean postoperative ODI, VAS and EQ5D scores improved (ODI 13.2 (range 0-30) vs 49.83 (range 15-71.1); p = .005). Equally this improvement was seen in the last follow-up (ODI 9.28 (range 0-35) vs 49.83 (range 15-71.1); p = .005). CT scan showed fusion grade A in 5 patients (41.6%), another 5 as grade B (41.6%) in Lenke classification. According to the Birdwell criteria 4 patients were classified as grade I (33.3%), 7 patients grade II (58.3%). None showed complications postoperatively or radiolucency in follow-up. CONCLUSIONS: Transdiscal fixation shows a good clinical outcome that is maintained throughout a long time period and provides a reliable and suitable fusion.

Does reintervention improve survival in recurrent glioblastoma? Facing a temporal bias in the literature.

BACKGROUND: Glioblastoma (GBM) is the most frequent intraaxial malignant brain tumour, in which recurrence management is a frequent and demanding issue. Recently, reintervention has emerged as a useful tool for treatment. However, some new evidence has shown that most of the articles published could have overestimated its effects. We aimed to analyse the effect on survival of reintervention considering it as a time-dependent variable and to compare it with classic statistical analysis. METHODS: We performed a retrospective study with GBM patients between 2007 and 2017. We compared the overall survival (OS) between reintervention and non-reintervention groups with time-dependent statistical methods (Simon-Makuch and landmarking methods and time-dependent multivariable Cox analysis) and compared them with those obtained with non-dependent time variable analysis. RESULTS: A total of 183 patients were included in the analysis and 44 of them were reoperated. The standard analysis with Kaplan-Meier and multivariable Cox regression of the cohort showed an OS of 22.2 months (95% CI 12.56-16.06) in the reintervention group and 11.8 months (95% CI 9.87-13.67) in the non-reintervention group (p < .001); and an HR 0.649 (95% CI 0.434-0.97 p = .035) for reintervention, demonstrating an increase in OS. However, time-dependent analysis with the Simon-Makuch test and the landmarking method showed that the relationship was not consistent, as this increase in OS was not significant. Moreover, time-dependent multivariable Cox analysis did not show that reintervention improved OS in our cohort (HR 0.997 95% CI 0.976-1.018 p = 0.75). CONCLUSIONS: There has been a temporal bias in the literature that has led to an overestimation of the positive effect of reintervention in recurrent GBM. However, reintervention could still be useful in some selected patients, who should be individualized according to prognostic factors related to the patient, biology of the tumour, and characteristics of surgical procedure.

How I do it? Lumbar cortical bone trajectory fixation with image-guided neuronavigation.

BACKGROUND: Cortical bone trajectory was described in 2009 to reduce screw loosening in osteoporotic patients. Since then, it has demonstrated improvements in biomechanical and perioperative results compared to pedicle screws, and it have been described as a minimally invasive technique. METHOD: We describe our experience with the technique assisted by 3D neuronavigation and review some of the complications and tools to avoid them together with limitations and pitfalls. CONCLUSION: Cortical bone trajectory guided by 3D neuronavigation helps to reduce the need for radiation and incidence of complications.

Intracranial intermediate-grade meningeal melanocytoma with increased cellular proliferative index: an illustrative case associated with a nevus of Ota.

Solitary primary melanocytic tumors of the central nervous system (CNS) represent a spectrum of lesions ranging from well-differentiated melanocytoma to melanoma. The association of a meningeal melanocytoma with an ipsilateral nevus of Ota is extremely rare, with only six cases reported in the literature to date. Only a minority of melanocytic tumors correspond to lesions of intermediate-grade malignancy, whose biological behavior and outcome remain undetermined. We report a new case of a 25-year-old man with a giant fronto-temporal intracranial meningeal melanocytoma associated with a congenital nevus of Ota, who suffered an acute neurological deterioration requiring an emergent surgical procedure. Despite total removal of the lesion, the patient did not recover from the operation due to a malignant infarct of the right hemisphere. The lesion showed no histological criteria of malignancy but did exhibit an elevated (8%) MIB-1/Ki-67 cell proliferative index, which suggested an intermediate-grade melanocytoma. In addition, its metabolic profile, determined by in vivo proton magnetic resonance spectroscopy (MRS), was similar to that observed in most high-grade gliomas. To our knowledge, this is the first case of a meningeal melanocytoma of intermediate grade associated with a nevus of Ota reported in the literature. Only two additional intermediate-grade melanocytomas showing an elevated MIB-1/Ki-67 labeling index have been previously reported. The MIB-1/Ki-67 labeling index may have potential prognostic value in helping the clinician to predict an aggressive clinical behavior and/or malignant progression for primary melanocytic neoplasms of the CNS.