History of spinal cord stereotaxy

Curated Model Development Using NEUROiD: A Web-Based NEUROmotor Integration and Design Platform

Decades of research on neuromotor circuits and systems has provided valuable information on neuronal control of movement. Computational models of several elements of the neuromotor system have been developed at various scales, from sub-cellular to system. While several small models abound, their structured integration is the key to building larger and more biologically realistic models which can predict the behavior of the system in different scenarios. This effort calls for integration of elements across neuroscience and musculoskeletal biomechanics. There is also a need for development of methods and tools for structured integration that yield larger in silico models demonstrating a set of desired system responses. We take a small step in this direction with the NEUROmotor integration and Design (NEUROiD) platform. NEUROiD helps integrate results from motor systems anatomy, physiology, and biomechanics into an integrated neuromotor system model. Simulation and visualization of the model across multiple scales is supported. Standard electrophysiological operations such as slicing, current injection, recording of membrane potential, and local field potential are part of NEUROiD. The platform allows traceability of model parameters to primary literature. We illustrate the power and utility of NEUROiD by building a simple ankle model and its controlling neural circuitry by curating a set of published components. NEUROiD allows researchers to utilize remote high-performance computers for simulation, while controlling the model using a web browser.

Intraspinal Delivery of Schwann Cells for Spinal Cord Injury

Cell transplant-mediated tissue repair of the damaged spinal cord is being tested in several clinical trials. The current candidates are neural stem cells, stromal cells, and autologous Schwann cells (aSC). Due to their peripheral origin and limited penetration of astrocytic regions, aSC are transplanted intralesionally as compared to neural stem cells that are transplanted into intact spinal cord. Injections into either location can cause iatrogenic injury, and thus technical precision is important in the therapeutic risk-benefit equation. In this chapter, we discuss how we bridged from transplant studies in large animals to human application for two Phase 1 aSC transplant studies, one subacute and one chronic. Preclinical SC transplant studies conducted at the University of Miami in 2009-2012 in rodents, minipigs, and primates supported a successful Investigational New Drug (IND) submission for a Phase 1 trial in subacute complete spinal cord injury (SCI). Our studies optimized the safety and efficiency of intralesional cell delivery for subacute human SCI and led to the development of new simpler techniques for cell delivery into subjects with chronic SCI. Key parameters of delivery methodology include precision localization of the injury site, stereotaxic devices to control needle trajectory, method of entry into the spinal cord, spinal cord motion reduction, the volume and density of the cell suspension, rate of delivery, and control of shear stresses on cells.

Cervical multilevel intraspinal stem cell therapy: assessment of surgical risks in Gottingen minipigs

STUDY DESIGN

Assessment of long-term surgical risks from multiple intraspinal cell injections.

OBJECTIVE

To prove that multilevel-targeted cell injection to the spinal cord can be a feasible and safe procedure.

SUMMARY OF BACKGROUND DATA

Neural cell transplantation has been proposed as a treatment for a variety of neurologic disorders, including degenerative, ischemic, autoimmune, and traumatic etiologies. Among these diseases, the lack of effective treatment for amyotrophic lateral sclerosis has prompted the search for cell-based neuroprotection or motor neuron-replacement therapies.

METHODS

Fifteen female minipigs, divided into 3 experimental groups, underwent either 5 or 10 unilateral injections of neural stem cells or 10 vehicle injections into the C3-C5 segments of the spinal cord, using a device and technique developed for safe and accurate injection into the human spinal cord. All animals received intravenous Tacrolimus (0.025 mg/kg) BID during the course of the study. Sensory and motor functions as well as general morbidity were assessed for 28 days. Full necropsy was performed and spinal cords were analyzed for graft survival. This study was performed under Good Laboratory Practice conditions.

RESULTS

Neither mortality nor permanent surgical complications were observed within the 28-day study period. All animals returned to preoperative baseline showing full motor function recovery. Graft survival was demonstrated by immunohistochemistry.

CONCLUSION

Clinically acceptable neural progenitor survival, distribution, and density were achieved using the number of injections and surgical techniques specifically developed for this purpose.

DITTMARAND THE HISTORY OF STEREOTAXY; ORRATS, RABBITS, AND REFERENCES

The renaissance of stereotactic functional neurosurgery has resulted in increased interest in its origins. Twenty articles concerning this field trace the history back to a paper published in 1873 by Dittmar: "Uber die Lage des sogenannten Gefaesszentrums in der Medulla oblongata" [On the location of the so-called vasomotor center in the medulla oblongata]. Few facts are presented. But, taken together, the impression given by the secondary sources is that Dittmar, in 1873, presented a guiding device for localization of intracranial structures for the positioning of electrodes/blades in the medulla oblongata in rats. Of the publications that cite Dittmar's original article as their only quoted source, half did not specify the inserted object and the animal of the experiment. The remaining articles reported either that the introduced object was an electrode or that the experiments were performed on rats. Dittmar's original article, however, did not report use of his apparatus for insertion of electrodes, nor did he use rats. All experiments were performed by making incisions in the medulla oblongata in rabbits. Dittmar's apparatus was constructed to allow more precision when performing incisions in the medulla oblongata than could be obtained performing incisions freehand. The incision point was chosen and the blade introduced with direct visual guidance. This has been described as "spatial localization of intracranial structures," "a special targeting instrument," or simply, "a guiding device." In our opinion, it can most properly be classified as a supportive arm.

Metastatic epidural cord compression

The past few years have witnessed remarkable advances in spinal imaging, radiosurgery, and minimally invasive procedures, such as vertebroplasty and kyphoplasty, as well as improved spinal surgical options with stabilization through instrumentation. These advances provide opportunities to treat patients with vertebral metastases and metastatic epidural spinal cord compression (MESCC) more successfully. In addition, a new study demonstrates that the time to develop motor weakness is an independent prognostic factor in outcome in patients with MESCC. These advances are reviewed.