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Background: The exoscope has emerged as an efficacious microscope in adult spinal neurosurgery providing improved operative field visibility and surgeon ergonomics. However, outcome data and feasibility are underrepresented in the pediatric literature. We present the largest case series aimed at assessing operative and clinical outcomes in pediatric patients undergoing various exoscope-assisted spinal surgeries., Methods: A retrospective review was conducted on all consecutive pediatric (age <18 years) spinal surgeries performed with the use of an exoscope by 3 senior surgeons at a single institution from 2020-2023. Demographics and clinical and operative outcomes were reviewed and analyzed., Results: Ninety-six exoscope-assisted pediatric spine surgeries were performed on 89 unique patients, 41 (42.7%) of which were male. The mean age at surgery was 12 (±5.3) years. Spinal cord detethering (55.8%) was the most common procedure performed. The overall mean operative time for all procedures was 155 (±86) minutes, and the mean estimated blood loss was 18 (±41) mL. The mean length of stay was 5.4 (±6.5) days. There were 14 (14.6%) patients with complications in this cohort. At final follow-up, 64 (83.1%) of symptomatic patients reported neurologic symptom improvement., Conclusions: Using the exoscope in a variety of pediatric spinal surgeries resulted in an acceptable average operative time, estimated blood loss, length of stay, and rate of neurologic symptom improvement. The exoscope appears to be an efficacious option for pediatric neurosurgical spinal procedures., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: Anatomic knowledge and insight depend on the cumulative contributions of anatomists over time, and eponyms pay homage to some of these individuals., Methods: A PubMed literature review identified 11 eponymous arteries of the brain and spinal cord., Results: The 11 eponyms include the artery of Adamkiewicz, the artery of Bernasconi and Cassinari, the artery of Davidoff and Schechter, the recurrent artery of Heubner, McConnell's capsular arteries, the artery of Percheron, the artery of Salmon, the Vidian artery, the arteria termatica of Wilder, the circle of Willis, and the artery of Wollschlaeger and Wollschlaeger., Conclusions: Eponyms remind us of an artery's importance and can improve our clinical acumen or technique. They have become an integral part of our day-to-day vocabulary, often without our historical knowledge of these anatomists. This report reviews these histories and the anatomy to deepen our appreciation of arterial eponyms in vascular neurosurgery., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Over the last decade, the growing body of work on spine pathology has led to developments and refinements in the areas of basic science, diagnosis and treatment of a variety of spine conditions. Scientific publications have a global impact on the international scientific community as they share vital information that can be applied by physicians worldwide to solve their everyday medical problems. The historical background of scientific publication in journals in Japan on the subject of spine is unclear., Methods: We performed a literature search for publications by Japanese spine surgeons regarding spine or spinal cord topics using an online database: Pubmed.gov (http://www.ncbi.nlm.nih.gov/pubmed/). The results were stored and analyzed at the Laboratory of Clinical Studies and Basic Models of Spinal Disorders of the University of Caxias do Sul. Results were limited to articles published from January 2000 to December 2013. The search terms used were "Japan" AND ("spine" OR "spinal diseases" OR "spinal cord" OR "spinal cord diseases" OR "vertebroplasty" OR "arthrodesis" OR "discectomy" OR "foraminotomy" OR "laminectomy" OR "denervation" OR "back injuries"). Japanese spine surgeons were defined as spine surgeons from orthopedic or neurosurgical specialties where the publication was affiliated with Japanese services., Results: A total of 16,140 articles were identified by the Medline search. Most of the articles were excluded based on information provided in the title and abstract as they were not related to spine surgery. This study comprised 1768 articles published in the Medline database by Japanese spine surgeons from 2000 to 2013. The number of publications rose in a linear fashion, with the number of papers published increasing by 5.4 per year (p = 0.038). In recent years the publications were increasingly performed in conjunction with the neurosurgery and orthopedics specialties., Conclusions: This study showed a clear increase in publications (on Medline) by Japanese spine surgeons over the last 14 years. While this is a positive development, there is also cause for concern as there is some evidence that the number of young scientists is declining in Japan. Special attention to educating researchers and improving resources for research is crucial to further increase the number and quality of Japanese publications., (Copyright © 2015 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background Context: No previous study has considered academic productivity and contributions to the literature among the faculty members of spine fellowship programs., Purpose: We sought to evaluate the total number of publications and measures of academic impact among faculty at spine surgical fellowship programs between 2011 and the present., Study Design: This study is based on a review of data publicly available on PubMed and Scopus., Patient Sample: Physicians listed as faculty at a spine fellowship program in the directory of the North American Spine Society (NASS)., Outcome Measures: The outcome measures were the number of publications between January 1, 2011 and August 31, 2014 and the h-index for 1996 to present (h-tot) and 2011 to present (h-pres) for faculty members., Methods: Fellowship programs and their characteristics were obtained from the directory of the NASS. Program-specific features, including academic affiliation, number of participating faculty, location, number of fellowship positions, dedicated research time, and presence of a research requirement for fellows, were abstracted. The number of publications for faculty at each program between January 1, 2011 and August 31, 2014 and the h-tot and h-pres were obtained from Scopus. Multivariable linear regression was used to identify statistically significant factors associated with increased academic productivity., Results: Among 75 fellowship programs, with 282 faculty members, there were 55 (73%) with academic affiliation. The average number of publications per faculty member (2011-2014) was 5.5 (standard deviation, 8.4; range, 0-54). The mean h-tot for programs was 13.6 (8.7, 0-37), and mean h-pres was 3.0 (2.2, 0-8.2). Academic affiliation (regression coefficient, 22.1; 95% confidence interval: 7.2, 37.0), and the number of fellows in a program (7.0, 0.9-13.2) was significantly associated with the total number of publications. Similar findings were encountered for average h-tot and h-pres., Conclusions: The descriptive statistics presented can help surgeons benchmark their performance and that of their fellowship, compared with others in the field. Determinations regarding characteristics associated with academic productivity may also help programs' fashion future strategic initiatives., (Copyright © 2015 Elsevier Inc. All rights reserved.)

The origin of spinal cord stereotaxy can be traced back to the 19th-century work of Woroshiloff, the pioneer of brain stereotaxy. The development of clinical brain stereotaxy began in the mid-20th century, but spinal cord stereotaxy lagged behind. The first stereotactic spinal cord surgery was successfully performed by Hitchcock for pain treatment in the 1960s, and surgery for urinary bladder hyperspasticity performed by Nádvorník followed several years later. Other stereotactic surgeries of the spinal cord movement system could not be considered until Slovak anatomist Čierny used animal experiments (with cats) to discover the exact location of motoneurons for the individual muscles in the anterior horns of the spinal cord. Having compared the data with the pattern of Riley's atlas based on microscopic investigation of the human spinal cord (only motoneuron groups without functional properties), the first stereotactic spinal cord atlas was transferred to human structures. With the construction of a universal spinal cord stereotactic device began a new era in spinal cord stereotaxy. The investigation of spinal cord movement functions will probably become the main focus of this discipline that aims to restore physiologic movement after spinal cord injury associated with paraplegia., (Georg Thieme Verlag KG Stuttgart · New York.)

Objective: This study explores the usefulness of virtual simulation training for learning to place pedicle screws in the lumbar spine., Methods: Twenty-six senior medical students anonymously participated and were randomized into two groups (A = no simulation; B = simulation). Both groups were given 15 minutes to place two pedicle screws in a sawbones model. Students in Group A underwent traditional visual/verbal instruction whereas students in Group B underwent training on pedicle screw placement in the ImmersiveTouch simulator. The students in both groups then placed two pedicle screws each in a lumbar sawbones models that underwent triplanar thin slice computerized tomography and subsequent analysis based on coronal entry point, axial and sagittal deviations, length error, and pedicle breach. The average number of errors per screw was calculated for each group. Semi-parametric regression analysis for clustered data was used with generalized estimating equations accommodating a negative binomial distribution to determine any statistical difference of significance., Results: A total of 52 pedicle screws were analyzed. The reduction in the average number of errors per screw after a single session of simulation training was 53.7% (P  =  0.0067). The average number of errors per screw in the simulation group was 0.96 versus 2.08 in the non-simulation group. The simulation group outperformed the non-simulation group in all variables measured. The three most benefited measured variables were length error (86.7%), coronal error (71.4%), and pedicle breach (66.7%)., Conclusions: Computer-based simulation appears to be a valuable teaching tool for non-experts in a highly technical procedural task such as pedicle screw placement that involves sequential learning, depth perception, and understanding triplanar anatomy.

Introduction: Toward the end of the nineteenth century, it was Gowers, Horsley and Macewen who first reported successful surgical procedures for the treatment of subdural extramedullary tumors. Following this, Church and Eisendrath as well as Putnam and Warren reported unsuccessful attempts to treat subpial spinal pathologies in their patients. Only at the beginning of the twentieth century did reports of successful interventions of this type accumulate. In the analysis of these case reports, the authors noticed a certain lack of accuracy about the anatomical allocations and descriptions of intra- and extramedullary spinal lesions. From this, the question of who actually carried out the pioneering works in the early twentieth century in the field of surgery of intramedullary pathologies arose., Methods: Analysis of the relevant original publications of Hans Brun and research on the poorly documented information about his life history by personally contacting contemporary relatives., Results: The literature analysis showed that the Swiss neurologist Otto Veraguth and surgeon Hans Brun made fundamental contributions to subpial spinal cord surgery at the very beginning of the last century that remain valid today. According to our research, Hans Brun should be remembered as the third surgeon (after von Eiselsberg and Elsberg) who successfully removed an intramedullary lesion in a patient., Conclusion: Brun should be remembered as an early and successful surgeon in this specialized field. His operative work is described in detail in this article. At the same time, his achievements in the fields of brain and disc herniation surgery are presented.

Introduction: Neurosurgery is a rapdily evolving speciality and has often taken a lead in adopting new technologies. Advancing technology however is not the only force driving change in this discipline. Other factors include an escalation in patient expectations, an increasing (and ageing) population and the prevailing economic conditions. The aim of our study was to analyse the trends in neurosurgical practice over a 10-year period., Materials and Methods: The details of every neurosurgical procedure performed at Wellington Regional Hospital from 2001 to 2011 were prospectively recorded in a relational database. This was then retrospectively interrogated to provide data for this study., Results: Neurosurgical practice has clearly evolved over the last decade. Predictable changes include a trend towards coiling rather than clipping of cerebral aneurysms, an increasing number of tumour resections (particularly for malignant glioma) coupled with the increased use of image guidance and endoscopy. The number of operations on the cervical spine has also increased although overall the number of procedures for spinal degenerative conditions has declined, perhaps reflecting local practice. The rates of craniotomy for trauma and burr holes for chronic subdural haematoma have remained essentially unchanged. We have demonstrated a significant increase in annual case-load that is disproportionate to any change in population size. Collaboration between specialties is increasingly evident., Conclusion: The most important changes have occured in the fields of neuro-oncology, vascular neurosurgery and spinal surgery. Inter-specialty collaboration is establishing itself as a model of care. These data may guide resource allocation for a population increasing both in number and in age.

Object: Simulation has become an important tool in neurosurgical education as part of the complex process of improving residents' technical expertise while preserving patient safety. Although different simulators have already been designed for a variety of neurosurgical procedures, spine simulators are still in their infancy and, at present, there is no available simulator for lumbar spine pathologies in pediatric neurosurgery. In this paper the authors describe the peculiarities and challenges involved in developing a synthetic simulator for pediatric lumbar spine pathologies, including tethered spinal cord syndrome and open neural tube defects., Methods: The Department of Neurosurgery of the University of Illinois at Peoria, in a joint program with the Mechanical Engineering Department of Bradley University, designed and developed a general synthetic model for simulating pediatric neurosurgical interventions on the lumbar spine. The model was designed to be composed of several sequential layers, so that each layer might closely mimic the tensile properties of the natural tissues under simulation. Additionally, a system for pressure monitoring was developed to enable precise measurements of the degree of manipulation of the spinal cord., Results: The designed prototype successfully simulated several scenarios commonly found in pediatric neurosurgery, such as tethered spinal cord, retethered spinal cord, and fatty terminal filum, as well as meningocele, myelomeningocele, and lipomyelomeningocele. Additionally, the formulated grading system was able to account for several variables involved in the qualitative evaluation of the technical performance during the training sessions and, in association with an expert qualitative analysis of the recorded sessions, proved to be a useful feedback tool for the trainees., Conclusions: Designing and building a synthetic simulator for pediatric lumbar spine pathologies poses a wide variety of unique challenges. According to the authors' experience, a modular system composed of separable layers that can be independently replaced significantly enhances the applicability of such a model, enabling its individualization to distinctive but interrelated pathologies. Moreover, the design of a system for pressure monitoring (as well as a general score that may be able to account for the overall technical quality of the trainee's performance) may further enhance the educational applications of a simulator of this kind so that it can be further incorporated into the neurosurgical residency curriculum for training and evaluation purposes.

Object: Health care reform debate includes discussions regarding outcomes of surgical interventions. Yet quality of medical care, when judged as a health outcome, is difficult to define because of impediments affecting accuracy in data collection, analysis, and reporting. In this prospective study, the authors report the outcomes for neurosurgical treatment based on point-of-care interactions recorded in the electronic medical record (EMR)., Methods: The authors' neurosurgery practice collected outcome data for 19 physicians and ancillary personnel using the EMR. Data were analyzed for 5361 consecutive surgical cases, either elective or emergency procedures, performed during 2009 at multiple hospitals, offices, and an ambulatory spine surgery center. Main outcomes included complications, length of stay (LOS), and discharge disposition for all patients and for certain frequently performed procedures. Physicians, nurses, and other medical staff used validated scales to record the hospital LOS, complications, disposition at discharge, and return to work., Results: Of the 5361 surgical procedures performed, two-thirds were spinal procedures and one-third were cranial procedures. Organization-wide compliance with reporting rates of major complications improved throughout the year, from 80.7% in the first quarter to 90.3% in the fourth quarter. Auditing showed that rates of unreported complications decreased from 11% in the first quarter to 4% in the fourth quarter. Complication data were available for 4593 procedures (85.7%); of these, no complications were reported in 4367 (95.1%). Discharge dispositions reported were home in 86.2%, rehabilitation center in 8.9%, and nursing home in 2.5%. Major complications included culture-proven infection in 0.61%, CSF leak in 0.89%, reoperation within the same hospitalization in 0.38%, and new neurological deficits in 0.77%. For the commonly performed procedures, the median hospital LOS was 3 days for craniotomy for aneurysm or intraaxial tumor and less than 1 day for angiogram, anterior cervical discectomy with fusion, or lumbar discectomy., Conclusions: With prospectively collected outcome data for more than 5000 surgeries, the authors achieved their primary end point of institution-wide compliance and data accuracy. Components of this process included staged implementation with physician pilot studies and oversight, nurse participation, point-of-service data capture, EMR form modification, data auditing, and confidential surgeon reports.

Modern computer graphics software has enabled the medical illustrator to render very complex anatomy by composing many different layers of drawings simultaneously. This and the author's capacity to take an "editorial" approach to compress several chronological events into a single, comprehensive two-dimensional illustration are analyzed in a step-by-step process. Through a series of images, the article provides a visual synopsis of the development of an illustration for an extensive clinical case: total sacrectomy performed through an all-posterior approach. Originally given as a slide presentation at the American Association of Neurological Surgeons Theodore Kurze Lecture in April 2011, the article provides some detailed notes on the techniques the author used to develop a comprehensive neurosurgical illustration., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Objective: To define and grade neurosurgical and spinal postoperative complications based on their need for treatment., Methods: Complications were defined as any deviation from the normal postoperative course occurring within 30 days of surgery. A four-grade scale was proposed based on the therapy used to treat the complications: grade I, any non-life-threatening complications treated without invasive procedures; grade II, complications requiring invasive management such as surgical, endoscopic, and endovascular procedures; grade III, life-threatening adverse events requiring treatment in an intensive care unit (ICU); and grade IV, deaths as a result of complications. Each grade was classified as a surgical or medical complication. An observational test of this system was conducted between January 2008 and December 2009 in a cohort of 1190 patients at the Hospital Italiano de Buenos Aires., Results: Of 167 complications, 129 (10.84%) were classified as surgical, and 38 (3.19%) were classified as medical complications. Grade I (mild) complications accounted for 31.73%, grade II (moderate) complications accounted for 25.74%, and grade III (severe) complications accounted for 34.13%. The overall mortality rate was 1.17%; 0.84% of deaths were directly related to surgical procedures., Conclusions: The authors present a simple, practical, and easy to reproduce way to report negative outcomes based on the therapy administered to treat a complication. The main advantages of this classification are the ability to compare surgical results among different centers and times, the ability to compare medical and surgical complications, and the ability to perform future meta-analyses., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The aging of the population in westernized countries constitutes an important issue for the health systems struggling with limited resources and increasing costs. Morbidity and mortality rates reported for neurosurgical procedures in the elderly vary widely. The lack of data on risk benefit ratios may result in challenging clinical decisions in this expanding group of patients. The aim of this paper is to analyze the elderly patients cohort undergoing neurosurgical procedures and any trend variations over time. The medical records of elderly patients (defined as an individual of 70 years of age and over) admitted to the Neurosurgical and Neuro-ICU Departments of a major University Hospital in Paris over a 25-year period were retrospectively reviewed. The analysis included: (1) number of admissions, (2) percentage of surgically treated patients, (3) type of procedures performed, (4) length of hospital stay, and (5) mortality. The analysis showed a progressive and significant increase in the proportion of elderly presenting for neurosurgical elective and/or emergency procedures over the last 25 years. The number of procedures on patients over 70 years of age increased significantly whereas the mortality dropped. Though the length of hospital stay was reduced, it remained significantly higher than the average stay. The types of procedures also changed over time with more craniotomies and endovascular procedures being performed. Age should not be considered as a contraindication for complex procedures in neurosurgery. However, downstream structures for postoperative elderly patients must be further developed to reduce the mean hospital stay in neurosurgical departments because this trend is likely to continue to grow.

Study Design: A cross-sectional survey of senior neurosurgical and orthopedic residents., Objective: To evaluate the confidence of senior orthopedic and neurosurgery residents in performing spinal surgical procedures and their need for further training. The content and exposure to spine training as well as anticipated practice profile were characterized., Summary of Background Data: Spinal surgery is performed by specialists with backgrounds in orthopedic surgery and neurosurgery. As this subspecialty evolves, the need to modify training programs to keep up with technological and medical advances becomes increasingly clear. The primary objective of this study was to evaluate the self-assessed confidence and perceived need for further training of senior orthopedic and neurosurgical residents in performing a number of spinal surgical procedures., Methods: An evaluation of self-assessed surgical competence of senior orthopedic and neurosurgery residents in Canada was undertaken by mail-out questionnaire. A follow-up questionnaire was mailed to nonresponders 3 months later. Survey results were summarized using SPSS statistical software, and descriptive and comparative analyses were performed., Results: Significant differences in time and exposure to spine training differentiated the neurosurgical and orthopedic residencies (37% and 16% of total residency time devoted to spine, respectively). Neurosurgical residents reported significantly higher levels of confidence for all 25 surgical procedures. Of those residents anticipating incorporating spine into their practice, 29% of neurosurgery residents planned on entering a spine fellowship compared with 17% of their orthopedic colleagues., Conclusions: Training in spine surgery constitutes a considerably larger proportion of neurosurgery residency than orthopedic residency. Neurosurgery residents graduate with significantly higher levels of confidence to perform spine surgery, while orthopedic residents report significantly higher need for additional training in spine surgery. The majority of neurosurgery graduates report that they will include spine in their clinical practice, while most orthopedic graduates will exclude it.

Introduction: Approximately 18% of conjoined twins (1 in 200,000 live births) are joined at the sacrum ("pyopagus"). As the joined structures are not life-threatening, there is generally a good prognosis, with time for investigation and planning of operative separation., Case Report: This paper reports on the management of pyopagus twin girls, the first in the UK delivered at 36 weeks by Caesarean section. The diagnosis had been made by ultrasound at 12 weeks' and confirmed by MRI scan at 26 weeks' gestation. Each twin had wasting and weakness below one knee, but no deficit in the other leg. The perineum had two urethras but only one anus. One infant had a colostomy in the immediate neonatal period. With appropriate further imaging, surgery was planned in two stages. First, a balloon expander was inserted in the bridging area. At 3 months of age a team comprising Plastic, Paediatric and Neurosurgeons undertook the definitive separation., Discussion: Details of the multidisciplinary planning, operative separation and follow-up of these two children will be discussed.

Background: The growing science and technology of various neurosurgical areas fosters subspecialization. The transmission of this expanding knowledge base to the neurosurgical resident becomes an increasing challenge. A survey of neurosurgical residency program directors was undertaken to evaluate their response to the budding subspecialization of spine surgery within general neurosurgery., Methods: A survey requesting background data, educational infrastructure and prevailing opinion was distributed to all 13 neurosurgical program directors in Canada. The responses were tabulated and results recorded. It is upon these results that conclusions and proposed directions are based., Results/conclusions: The current practice of the overwhelming majority of Canadian academic neurosurgical centers is to have neurosurgical spinal subspecialists working under the umbrella of the general neurosurgical division. A large percentage of neurosurgical program directors in Canada believe that the management of spinal disease, including both intradural procedures and instrumentation, is and should remain an integral part of general neurosurgical training. A consensus statement regarding the requirements of neurosurgical training in spinal disorders is the expressed desire of almost all program directors. A proposed direction and resolution is discussed.

Tenting of the arachnoid with intact trabeculae to facilitate and maintain rotation of the cord during the resection of ventrally or ventrolaterally located spinal meningiomas is proposed. The arachnoid-trabeculae tenting acts as a self-retaining retractor, and prevents overlapping of the cord onto the tumor due to gravity.

Knowledge of the role and hazards of transoral surgery has expanded rapidly, but the application of this technique in children has been limited. To assess its usefulness, 27 pediatric patients who underwent transoral surgery between 1985 and 1994 were studied. Transoral surgery was performed for irreducible anterior neuraxial compression at the craniovertebral junction caused by basilar impression, atlantoaxial subluxation with pseudotumor, or chordoma. The patients ranged in age from 3 to 17 years. Symptomatic presentation varied widely, but 89% had significant neurological deficits before surgery. No patient with normal strength deteriorated after surgery. Of the 16 patients with a preoperative motor deficit, nine improved rapidly, three were unchanged, and four significantly worsened in the perioperative period. Those with mobile atlantoaxial subluxation were most vulnerable to surgically related neurological morbidity. Twenty-four patients were alive for long-term follow-up study (average 5.7 years, range 1-9.2 years). Of those with preoperative weakness, nine improved one Frankel grade, four remained the same, and one deteriorated from Frankel Grade D to C. Swallowing and speech worsened in five patients; this occurred only after resection of lesions above the foramen magnum (p<0.05) when rostral pharyngeal disruption resulted in velopharyngeal dysfunction. This study, unlike previous reviews of pediatric transoral operations, leads the authors to suggest that although transoral surgery can be effective, it also carries a significant risk of neurological injury in patients with symptomatic spinal cord compression and it is also associated with long-term swallowing and speech difficulties.

The use of new endoscopic techniques to conduct a thoracic discectomy is presented. The development of these endoscopic techniques through live porcine and cadaver models are outlined. It is concluded that the use of multiple ports for the endoscopic approach to the thoracic spine provides an exposure to the anterior and lateral spinal theca that is equal to the exposure afforded by the more extensive thoracotomy. Current techniques are being developed for transperitoneal and retroperitoneal endoscopic lumbar spine surgery.

The most satisfactory method of prone positioning for the posterior approach to the spine and posterior fossa has been influenced by the necessity of providing good operating condition: prone position without abdominal and thoracic compression with a patient's head in the neutral position. Communication between the cava veins and the vertebral venous plexus explain that induce positioning can produce an excessive venous intraoperative bleeding with decreased surgical visibility. Furthermore venous return to the heart decreased resulting in some degree of impaired cardiac output. Hemodynamic disturbances of cerebral or spinal cord bloods flows can occurred.

The decade of the 1990's has provided neurosurgery with multiple challenges and opportunities. Numerous developments hold a promise for making the 1990's the most rewarding decade of the 20th century for neurosurgery. The "Decade of the Brain" resolution, adopted by the United States House and Senate and signed into law by President Bush in 1989, has provided the specialty with staggering opportunities. Neurosurgery and the basic and clinical neurosciences would be strengthened by the development of a major new philanthropic organization called the "American Brain Association" that would carry the activities of the Decade of the Brain into the 21st century. Major efforts are being made to improve organized neurosurgery's responsiveness to member needs. These include the strategic planning project undertaken by the Board of Directors of the American Association of Neurological Surgeons (AANS) and efforts to strengthen the Joint Council of State Neurosurgical Societies. The AANS has been extremely active in representing the specialty in legislative matters in Washington and in multiple other forums. This Association has joined The American Board of Neurological Surgery and the Residency Review Committee in responding to orthopedic surgery's proposal for spine fellowships. It is proposed that the logo of the state, regional, and national neurosurgical societies be changed to depict our involvement in spinal surgery (as well as brain surgery) because spinal surgery represents more than half of the total effort of this specialty. The standards of worth and value that provide the driving force behind our work emphasize the need to grow in compassion as manifested by our kindness, sincerity, and concern as we grow in professional competence as reflected by our training, knowledge, and skill.

This paper describes a preparation in which the skeletal neuromuscular system of the hind limb of the adult cat is rendered permanently quiet with respect to electrical and contractile activity. The surgical method, regime for maintaining the health of the cats, and the condition of the cats are reported in detail. The characteristics of the isolated neuromuscular system are briefly summarized. The lumbosacral spinal cord carrying the innervation to the lower hind limb was surgically isolated from excitatory inputs from both dorsal root afferent fibers and upper motoneurons. This was accomplished by a bilateral dorsal rhizectomy between two transections of the cord, just rostral to the L5 segment and approximately at the S3 segment. The laminectomy was restricted to retain laminar structures sufficient to protect the cord from mechanical stimulation. During the rostral transection, the ventral artery was spared, preserving the blood supply to the ventral region of isolated cord. Daily maintenance and surveillance procedures were extremely important, but simple and brief. With strict adherence to procedures for both surgery and care, the cats remained healthy except for bladder infections, and their hind legs were in chronic flaccid paralysis.

With a seventh of 233 neuro-surgical patients operated on in the area of the spinal canal, an acute or sub-acute transverse syndrome had become manifest before operation. The analysis of these cases shows that 2 out of 12 cervical, and 12 out of 100 lumbar cases of dislocation of the disk cause an acute or sub-acute transverse lesion of the cord with paraplegia. In 56 cases of intradural extra-medullary tumours, no acute development was observed. However, this was seen in 55% of the extra-dural tumour growths. The role of a vasal component in the event of speedy development of the transverse symptomatology in such cases is mentioned.

Excluding specific neurosurgical indications for cortical localization or peripheral nerve surgery, the use of sensory evoked potentials as a monitor in the operating room should be controversial at this time. Whether appropriate or not, legal and medical forces have largely established the use of somatosensory evoked potential monitoring as a standard during procedures that threaten the integrity of the spinal cord. The author believes that such monitoring should not replace the use of a "wake-up" test during these procedures because of the recognized possible occurrence of false negative results (i.e., normal evoked potentials despite abnormal spinal cord function). Another apparent established practice is monitoring of brainstem auditory evoked potentials to recognize the onset of disturbance in the auditory system. It has not been established that other recommended evoked potential monitoring practices, such as somatosensory evoked potential monitoring for such purposes as recognizing cerebral ischemia, or brainstem auditory evoked potential monitoring for recognizing untoward medullary stimulation, are as good as or better for these purposes than currently recognized and simpler monitors.

The neurosurgeon can play a significant role in the management of chronic pain. This potential is all to often unrealized or distorted by a lack of knowledge about patients who are suffering from chronic pain. Patient selection is the most important determinant of successful surgical therapy. Patients with chronic pain due to a neoplasm should be offered prompt, definitive neurosurgical intervention. Neurosurgical therapy is less likely to be successful if the pain is secondary to benign disease; tic douloureux is an exception to this rule. If chronic pain behavior is not primarily due to noxious peripheral input, surgery is unlikely to yield any long-term benefit. Augmentation of input by skin stimulation or electrical stimulation of various regions in the peripheral and central nervous system may become important therapeutic procedures for the neurosurgeon.

While pain can be a most useful symptom, it becomes a problem requiring attention when it causes or increases the patient's anxiety, prevents sleep, or starts the patient on a vicious cycle of increasing doses of narcotics with concomitant depression, anorexia, and lethargy. Various surgical modalities and their indications are discussed.