Secondary spinal cord injury (SSCI) is the second stage of spinal cord injury (SCI) and involves vasculature derangement, immune response, inflammatory response, and glial scar formation. Bioactive additives, such as drugs and cells, have been widely used to inhibit the progression of secondary spinal cord injury. However, the delivery and long-term retention of these additives remain a problem to be solved. In recent years, hydrogels have attracted much attention as a popular delivery system for loading cells and drugs for secondary spinal cord injury therapy. After implantation into the site of spinal cord injury, hydrogels can deliver bioactive additives in situ and induce the unidirectional growth of nerve cells as scaffolds. In addition, physical and chemical methods can endow hydrogels with new functions. In this review, we summarize the current state of various hydrogel delivery systems for secondary spinal cord injury treatment. Moreover, functional modifications of these hydrogels for better therapeutic effects are also discussed to provide a comprehensive insight into the application of hydrogels in the treatment of secondary spinal cord injury.

BACKGROUND Spinal schwannoma is a common benign tumor. However, the high recurrence rate and incidence of surgical complications are unsolved problems. OBJECTIVE To propose a morphological classification of spinal schwannoma based on tumor-membrane relationships to increase the gross total resection (GTR) rate and to decrease the incidence of surgical complications. METHODS Histological techniques were used to study 7 adult cadavers. Following picrosirius staining, the membranes around the nerve root were observed under a microscope. Data from 101 patients with spinal schwannoma were also collected for clinical analysis. RESULTS The sleeve around the spinal nerve root consisted of dura and arachnoid tissues. The space between them gradually narrowed and fused at the proximal pole of the nerve root ganglion. Spinal schwannomas were divided into 4 types based on membranous structure: intrapial (type I), subarachnoidal (type II), intra- and extradural (type III), and extradural growth (type IV). Types II and III were further subdivided into 2 subtypes. GTR was achieved in all patients (100%), with no tumor recurrence during follow-up. Overall functional status significantly improved postoperatively. A total of 59 patients (92%) showed improvement or significant improvement postoperatively. There was no difference in surgical outcomes among the tumor classifications (P = .618). No intraoperative vertebral artery injuries or postoperative cerebrospinal fluid fistula occurred. CONCLUSION Spinal schwannoma classification based on a membranous hierarchy provides an intuitive platform for preoperative planning and intraoperative safety. This classification scheme may help surgeons better define surgical goals and anticipate or even avoid complications from resection.

ObjectiveWe retrospectively assessed the surgical results of PBC with preoperative multimodal image fusion and intraoperative Dyna Computed Tomography (CT) in 24 patients with primary trigeminal neuralgia (PTN) to explore a valuable aid for Percutaneous balloon compression (PBC).MethodsWe studied the data of 24 patients with PTN. All patients underwent PBC and were assessed with preoperative multimodal image fusion [computed tomography (CT) and magnetic resonance imaging (MRI)] and intraoperative Dyna CT in the Department of Neurosurgery of Zhuhai People’s Hospital between October 2020 and September 2021. Multimodal image fusion—three-dimensional (3D) reconstruction of CT and MRI data—was performed using 3D-Slicer software, and preoperative evaluation was performed according to the results of image fusion. Dyna CT was used to dynamically observe the position and shape of the metallic hollow introducer and Fogarty catheter and balloon during the operation to guide the operation in real time. We performed follow-up assessments each month and summarized the clinical characteristics, surgical effects, and complications in all patients.ResultsSurgery was successful for all patients; the patients reported immediate pain relief. Surgical complications included facial numbness in 24 patients (100%), mild masseter weakness in three (12.5%), herpes zoster in three (12.5%), and balloon rupture in one (4.2%). None of the patients had serious surgical complications. The mean follow-up time was 9.6 ± 2.7 months. During the follow-up period, 22 patients (91.7%) experienced no recurrence of pain, and two patients (8.3%) experienced recurrence of pain, of which one underwent secondary PBC surgery.ConclusionsPreoperative multimodal image reconstruction can help fully evaluate PBC surgery, clarify the etiology, and predict the volume of contrast medium required during the operation. It provided important assistance for PBC treatment of trigeminal neuralgia patients when preoperative multimodal image fusion is combined with intraoperative Dyna CT.