Spinal cord injury (SCI) distinguishes itself from peripheral nerve injury by causing devastating and irreversible damage to the spine, resulting in profound motor, sensory, and autonomic dysfunction. The ensuing complex microenvironment of SCI, characterized by hemorrhage, inflammation, and scar formation, poses substantial challenges to regeneration and complicates numerous transplantation strategies. Recent research has shifted its focus towards manipulating the intricate SCI microenvironment to enhance regeneration, with some approaches demonstrating significant therapeutic efficacy. Consequently, the reconstruction of an appropriate microenvironment post-transplantation emerges as a potential therapeutic solution for SCI. This review aims to provide a comprehensive overview, firstly summarizing the influential compositions of the microenvironment and their diverse effects on regeneration. Secondly, we highlight recent research employing various transplantation strategies to modulate distinct microenvironments induced by SCI, aiming to facilitate regeneration. Lastly, we discuss prospective transplantation strategies for SCI, emphasizing the importance of addressing the complex microenvironment for successful therapeutic outcomes.

Spinal cord injury is a devastating condition that leaves permeant disability. Surgical decompression and stabilization with various pharmacological treatments have been tried to prevent secondary injury, however, their results have been disappointing. Therefore, novel therapeutic options are required enthusiastically. Cell transplantation that has the potential of neuroregenerative and neuroprotective ability is regarded as a promising remedy. We would like to describe about the micro-anatomy and the mechanism of injury of spinal cord injury. We also delineate transplanted cells; embryonic stem cell, induced pluripotent stem cell, mesenchymal stem cell as stem cells and Schwan cell, olfactory ensheathing cell as supporting cells with brief reviews of their experimental results.

Purpose
To assess the volume of fusion mass after posterior lumbar interbody fusion (PLIF) using Hounsfield units methods.
Methods
The present study was within the frame work about a prospective observational cohort study to compare the surgical outcomes of a single-level PLIF for LSS between the local bone (LbG) and local bone plus hydroxyapatite groups (LbHa). The fusion material for each case was determined by the amount of available local bone. After the fusion material was chosen, patients were assigned to either the LbG group (n=20) or the LbHa group (n=20). The primary outcome was the assessment of fusion mass volume in each group.
Results
We used the new method using Hounsfield units for volumetric assessments of interbody fusion mass. There was no difference in fusion rates or volume of the fusion mass between the 2 groups.
Conclusions
Hounsfield unit method, that is the CT-based summation method using a cross-sectional slice, can be applied usefully to other areas of orthopaedics.