Methods: Seventy-four patients (99 levels) underwent trans-tubular MISS between March 2018 and January 2019. Five patients were excluded: one had pyogenic discitis, two had revisions, and two were trans-tubular transoral. In total, we analyzed 69 for operating time, blood loss, and complications. The learning curve graph was plotted using the surgical time for each procedure. Surgeons were asked to rate their satisfaction with image quality, ability to maintain ergonomic posture, and efficient target site treatment. Results: For tubular microdiscectomy, the operating time plateaued after six cases, and for tubular decompression and minimally invasive transforaminal lumbar interbody fusion, the operating time plateaued after nine cases. Mean operating time was significantly reduced after the plateau. Complications included four cases of dural tear. All patients improved symptomatically, and there were no postoperative neurological deficits. Conclusions Use of the exoscope has a short learning curve. Surgeons benefit from improved ergonomic posture during surgery, and resident teaching appears to be good. The only drawback is the need to rearrange the operating table setup. Complications were comparable to those when using the surgical microscope. An exoscope with hybrid digital visualization provides excellent visualization, depth perception, clarity, and precision target site treatment.

Background: Detection of neuraxial abnormality in neurologically asymptomatic adolescent idiopathic scoliosis (AIS) is crucial prior to surgery. It can only be detected on magnetic resonance imaging (MRI), which was not routinely done in this group of patient. On the other hand, whole spine radiographs for measurement of Cobb angle have been routinely included during clinic follow-up. This study aimed to determine the correlation between Cobb angle progression and neuraxial abnormality finding on MRI in asymptomatic AIS. Methods: A retrospective study was conducted in the Orthopaedic department of a tertiary hospital. Patients with asymptomatic AIS aged 10-20 years who attended scoliosis clinic from year 2007 to 2010 was reviewed. Patients who had whole spine MRI and two vertebral radiographs at least one year apart were further selected. Statistical analysis was done to see the association between Cobb angle progression and neuraxial abnormality on MRI. Results: The mean age at first presentation was 14.4 years old. Female (n=249) to male (n=50) ratio was 5:1. Only 19 patients fulfilled the selection criteria. There were 5 patients (26.3%) who had neuraxial abnormalities. The mean curve progression was 7.05° (range from -5° to 28°). Patients with and without neuroaxial abnormality showed mean curve progression of 0.6º and 9.36° respectively. There was no significant association between Cobb angle progression and neuroaxial abnormality (p=1.000). Conclusion: Cobb angle progression is not a reliable indicator for predicting neuroaxial abnormality in patients with asymptomatic AIS. However, this study stressed the need to perform MRI prior to operation to document any associated neuraxial abnormality in clinically asymptomatic AIS patients.