Competency based residency training: the next advance in graduate medical education.
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Clinical Competence↗
Biomedical subjects
D M Long
Publications and source records attributed to D M Long.
Renoprotective effects of a novel inhibitor of advanced glycation.
AIMS/HYPOTHESIS: ALT-946, an inhibitor of advanced glycation with a minimal inhibitory effect on nitric oxide synthase, was compared with aminoguanidine in experimental diabetic nephropathy. METHODS: In vitro and in vivo assays were used to assess the ability of ALT-946 to inhibit AGE-protein cross-link formation. Diabetic animals were randomly allocated into groups receiving aminoguanidine for 32 weeks, ALT-946 or vehicle (untreated). As a delayed intervention protocol, an additional diabetic group was treated with ALT-946 from week 16 to week 32 of the study. Non-diabetic rats were studied concurrently. Systolic blood pressure, body weight, plasma glucose, glycated haemoglobin and urinary albumin excretion were measured serially. Accumulation of advanced-glycation end products in the kidney was assessed by immunohistochemistry. RESULTS: The ALT-946 inhibitor was more potent than aminoguanidine in inhibiting AGE-protein cross-linking both in vitro and in vivo. Increased albuminuria observed in diabetic rats was attenuated in all three treatment groups. We found no difference in body weight, blood pressure or glycaemic control with any of the treatments. The untreated diabetic group had a twofold increase in glomerular staining for advanced-glycation end products compared with the diabetic groups which received treatment. CONCLUSION/INTERPRETATION: ALT-946 is a potent inhibitor of advanced renal glycation end-product accumulation and reproduces the renoprotective effects of aminoguanidine. Therefore, ALT-946 should be considered as a treatment for preventing or retarding diabetic nephropathy.
Animals↗
The treatment of meningiomas in the region of the cavernous sinus.
The diagnosis and treatment of meningiomas of the cavernous sinus remains a controversial part of skull base surgery practice. The most common presenting symptom headache is nonspecific. Visual loss and oculomotor disturbance are the next likely symptoms and signs. It is possible to achieve total tumor removal in about 50% of patients, but an increase in cranial nerve dysfunction occurs in nearly as many. Improvement of neurological function, except for vision, is unusual. Because of the risk of complicating cranial nerve dysfunction by surgery, focused radiation as an alternative treatment has been explored in a small number of patients. Unfortunately, volume reduction is only seen in about one-third, but risks do appear to be low and nearly 60% of patients recorded have improvement in preoperative cranial nerve deficits. With these indolent tumors, much longer follow-ups are required before the role of focused radiation can be assessed.
Cavernous Sinus↗
Two telomerase reverse transcriptases (TERTs) expressed in Candida albicans.
The human pathogenic yeast Candida albicans contains two telomerase reverse transcriptase (TERT) genes. CaTERT1 and CaTERT2 appear either to be two alleles of the same gene or two entirely different genes that encode 867-residue proteins that differ by five amino acids. Both TERTs have a calculated pI of 9.5 and a M(r) of 100.9 kDa and are the smallest TERTs identified to date. Both genes appear to be expressed. Based on sequence similarity between CaTERT1 and the Saccharomyces cerevisiae orthologue Est2p, we suggest a revised alignment for motif E of Est2p. The identification of these TERT genes provides the first opportunity to study telomerase in an important human pathogen.
Alleles↗
Hemangioblastomas of the central nervous system in von Hippel-Lindau syndrome and sporadic disease.
OBJECTIVE: The presentation, screening, management, and clinical outcomes of patients who presented to our institution from 1973 to 1999 with central nervous system (CNS) hemangioblastomas in von Hippel-Lindau (VHL) syndrome and sporadic disease were analyzed. METHODS: The surgical pathology database of our institution was searched to identify all patients with histologically verified CNS hemangioblastomas occurring from 1973 to 1999. The medical, radiological, surgical, pathological, and autopsy records from these patients were reviewed retrospectively and statistically analyzed. RESULTS: Forty patients (21 males and 19 females) presented with CNS hemangioblastomas. Twenty-five patients (62%) harbored sporadic hemangioblastomas. Fifteen patients (38%) had VHL syndrome. These 40 patients presented with 61 hemangioblastomas (8 patients had multiple lesions). Ten patients (25%) harbored spinal cord hemangioblastomas (5 patients had multiple lesions). Patients with VHL disease tended to present with neurological symptoms and signs at a younger age than patients with sporadic disease (P = 0.09), to present with multiple lesions (53%), and to develop new lesions (rate, 1 lesion/2.1 yr). Hemangioblastomas of the spinal cord were more prevalent in patients with VHL syndrome (P = 0.024). Neuroradiological screening of patients with VHL syndrome allowed identification of more than 75% of new lesions before they became symptomatic. Sixty-six surgical procedures were performed (12 patients required multiple operations). Six patients with VHL syndrome required surgery for new lesions. Surgical complications occurred in six patients (15%). Symptom resolution or arrest of progression at 1 year was documented in 88% of patients. Recurrence of symptoms from partially resected lesions occurred in eight patients (20%). No deaths associated with surgery occurred. One patient with sporadic disease and one patient with VHL syndrome (5%) died as a result of late medical complications from CNS hemangioblastomas. CONCLUSION: Surgical outcomes for patients with CNS hemangioblastomas are favorable. However, management of hemangioblastomas is a more difficult and prolonged endeavor for patients with VHL syndrome. In patients with VHL syndrome, neuroradiological screening allows identification of lesions before they become symptomatic. Because patients with VHL syndrome are at risk for development of new lesions, they require lifelong follow-up.
Adolescent↗
Sine qua non: the formulation of a theory of neurosurgery.
Fundamental postulates underlying the fabric of biomedicine are rarely discussed, much less seen in print. Scientific surgery and its subspecialties are relatively new fields, and their philosophical basis has received little attention since Halsted's day. During the last quarter century, we have "reinvented" neurosurgery, and a concatenation of forces is escalating that is further accelerated by technological change. Social, economic, political, and scientific climates concurrently exert unusually stressful influences on all practitioners, irrespective of the individual setting. This provides a reason to reexamine what neurosurgeons do and why, and to attempt to define the guidelines of theoretical basis for the specialty of neurosurgery and its procedures. This article examines the accomplishments of past generations in an effort to establish surgical substrata and proceeds to attempt to readdress elements of a theoretical basis of our current practice.
Humans↗
Neurologic deficits after cervical laminectomy in the prone position.
New neurologic deficits are known to occur after spine surgery. We present four patients with cervical myeloradiculopathy who underwent cervical laminectomy, fusion, or both in the prone position, supported by chest rolls. Three patients were intubated and positioned while awake, whereas the fourth patient was positioned after induction. Surgeries were successfully carried out, except for transient episodes of relative hypotension intraoperatively. On recovery from anesthesia, all patients were noted to have new neurologic deficits. Immediate CT myelography or surgical reexploration was unremarkable. All patients improved gradually with administration of high-dose steroids and induction of hypertension. Use of the prone position with abdominal compression may compromise spinal cord perfusion and lead to spinal cord ischemia. The use of frames that prevent abdominal compression, as well as avoidance of perioperative arterial hypotension, is important in maintaining adequate spinal cord perfusion during and after decompressive spinal cord surgery.
Adult↗
The Atlanta Urban Networks Study: a blueprint for endemic transmission.
OBJECTIVE: To study prospectively social networks and behavior in a group of persons at risk for HIV because of their drug-using and sexual practices, with particular emphasis on the interaction of risks and concomitant network structure. METHODS: A longitudinal study was conducted of 228 respondents in Atlanta, Georgia in six inner-city community chains of connected persons, interviewing primary respondents and a sample of their contacts every 6 months for 2 years. Ascertained were: HIV and immunologic status; demographic, medical, and behavioral factors; and the composition of the social, sexual, and drug-using networks. RESULTS: The prevalence of HIV in this group was 13.3% and the incidence density was 1.8% per year. Substantial simultaneity of risk-taking was observed, with a high level of both non-injecting (crack, 82%) and injecting (heroin, cocaine or both, 16 30%) drug use, the exchange of sex or money for drugs by men (approximately 35%) and women (57-71%), and high frequency of same-sex sexual activity by men (9.4%) and women (33%). The intensity of interaction, as measured by network features such as microstructures and concurrency, was significantly greater than that observed in a low prevalence area with little endemic transmission. CONCLUSION: The traditional hierarchical classification of risk for HIV may impede our understanding of transmission dynamics, which, in the setting of an inner-city population, is characterized by simultaneity of risk-taking, and moderately intense network interactions. The study provides further evidence for the relationship of network structure to transmission dynamics, but highlights the difficulties of using network information for prediction of individual seroconversion.
Adult↗
Intracanalicular schwannoma of the facial nerve: a manifestation of neurofibromatosis type 2.
Primary facial nerve tumors, which are relatively uncommon, can present a diagnostic dilemma based on their location and variable pattern of symptoms. Of primary cranial nerve tumors, schwannomas of the facial nerve rank third in frequency after those of the eighth and fifth cranial nerves. We report an illustrative case of an intracanalicular schwannoma associated with several central nervous system tumors, consistent with neurofibromatosis type 2. Initially assumed to be an eighth cranial nerve tumor, the schwannoma was found intraoperatively to arise from the facial nerve. Early diagnosis and treatment enabled excision of the tumor without sacrifice of the facial nerve. Facial nerve schwannomas can resemble acoustic schwannomas in their clinical presentation. Only a heightened level of clinical vigilance will point to the correct diagnosis and result in an optimal therapeutic outcome for patients with these rare tumors.
Cranial Nerve Neoplasms↗
Neodymium:YAG laser posterior capsulotomies performed by residents at a Veterans Administration Hospital.
PURPOSE: To assess the initial efficacy of neodymium:YAG (Nd:YAG) laser posterior capsulotomies performed by residents at a teaching institution and to evaluate the associated complications over an extended follow-up. SETTING: Department of Ophthalmology, Edward Hines, Jr. Veterans Administration Hospital, Hines, Illinois, USA. METHODS: This retrospective noncomparative case review comprised 212 pseudophakic eyes having Nd:YAG laser posterior capsulotomies from April 1992 through March 1995. Evaluated were postoperative changes in best corrected visual acuity (BCVA), intraocular pressure (IOP) elevations, and complications related to the procedure. RESULTS: In all 212 eyes, Snellen visual acuity was obtained at least 1 week after the capsulotomy. The BCVA in 96 eyes (45.3%) improved by 3 or more lines, in 43 (20.3%) by 2 lines, and in 51 (24.1%) by 1 line. Nineteen eyes (9.0%) did not improve by 1 or more lines, and 3 eyes (1.4%) had decreased Snellen acuity. All but 4 eyes with less than 1 line of improvement had underlying ocular pathology or a previous incomplete capsulotomy. For evaluation of postoperative complications, long-term follow-up was available for 133 of 212 eyes (62.7%). The mean follow-up for this group was 3.18 years. Postoperative complications were found in 14 of these eyes (10.5%). Nine (6.8%) had a rise in IOP greater than 10 mm Hg after the capsulotomy. One eye (0.8%) developed a persistent iritis, 2 (1.5%) had vitreous prolapse into the anterior chamber, and 2 (1.5%) developed rhegmatogenous retinal detachments. CONCLUSION: Postoperative Snellen acuity results and complication rates compare favorably with those in previous studies. The results indicate that Nd:YAG laser posterior capsulotomies performed by residents with attending supervision are safe, effective, and carry a low associated complication rate over a long follow-up.
Clinical Competence↗
Paraplegia after cystectomy and epidural anesthesia.
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Anesthesia, Epidural↗
Competency-based residency training: the next advance in graduate medical education.
The goal of all graduate medical education is to ensure that the graduating physician is competent to practice in his or her chosen field of medicine. The evaluation of a resident's competency to practice, however, has never been clearly defined, nor has the fixed period of time given for residency training in each specialty been shown to be the right amount of time for each individual resident to achieve competency. To better ensure that new physicians have the competencies they need, the author proposes the replacement of the current approach to residents' education, which specifies a fixed number of years in training, with competency-based training, in which each resident remains in training until he or she has been shown to have the required knowledge and skills and can apply them independently. Such programs, in addition to tailoring the training time to each individual, would make it possible to devise and test schemes to evaluate competency more surely than is now possible. The author reviews the basis of traditional residency training and the problems with the current training approach, both its fixed amount of time for training and the uncertainty of the methods of evaluation used. He then explains competency-based residency education, notes that it is possible, indeed probable, that some trainees will become competent considerably sooner than they would in the current required years of training, quotes a study in which this was the case, and explains the implications. He describes the encouraging experience of his neurosurgery department, which has used competency-based training for its residents since 1994. He then discusses issues of demonstrating competency in procedural and nonprocedural fields, as well as the evaluation of competency in traditional and competency-based training, emphasizing that the latter approach offers hope for better ways of assessing competency.
Baltimore↗
Microanatomical variations in the cerebellopontine angle associated with vestibular schwannomas (acoustic neuromas): a retrospective study of 1006 consecutive cases.
OBJECT: Great advances in neuroimaging, intraoperative cranial nerve monitoring, and microsurgical technique have shifted the focus of acoustic neuroma surgery from prolonging life to preserving cranial nerve function in patients. An appreciation of the vascular and cranial nerve microanatomy and the intimate relationship between neurovascular structures and the tumor is essential to achieve optimum results. In this paper the authors analyze the microanatomical variations in location of the facial and cochlear nerves in the cerebellopontine angle (CPA) associated with acoustic neuromas and, additionally, describe the frequency of involvement of surrounding neural and vascular structures with acoustic tumors of varying size. The authors base these findings on their experience with 1006 consecutive patients who underwent surgery via a retrosigmoid or translabyrinthine approach. METHODS: Between July 1969 and January 1998, the senior author (D.M.L.) performed surgery in 1022 patients for acoustic neuroma: 705 (69%) via the retrosigmoid (suboccipital); 301 (29%) via the translabyrinthine; and 16 (2%) via the middle fossa approach. Patients undergoing the middle fossa approach were excluded from the study. The remaining 1006 patients were subdivided into three groups based on tumor size: Group I tumors (609 patients [61%]) were smaller than 2.5 cm; Group II tumors (244 patients [24%]) were between 2.5 and 4 cm; and Group III tumors (153 patients [15%]) were larger than 4 cm. The senior author's operative notes were analyzed for each patient. Relevant cranial nerve and vascular "involvement" as well as anatomical location with respect to the tumor in the CPA were noted. "Involvement" was defined as adherence between neurovascular structure and tumor (or capsule), for which surgical dissection was required to free the structure. Seventh and eighth cranial nerve involvement was divided into anterior, posterior, and polar (around the upper or lower pole) locations. Anterior and posterior locations were further subdivided into upper, middle, or lower thirds of the tumor. The most common location of the seventh cranial nerve (facial) was the anterior middle third of the tumor for all groups, although a significant number were found on the anterior superior portion. The posterior location was exceedingly rare (< 1%). Interestingly, patients with smaller tumors (Group I) had an incidence (3.4%) of the seventh cranial nerve passing through the tumor itself, equal to that of patients with larger tumors. The most common location of the eighth cranial nerve complex was the anterior inferior portion of the tumor. Not surprisingly, larger tumors (Group III) had a higher incidence of involvement of fourth cranial nerve (41%), fifth cranial nerve (100%), ninth-11th cranial nerve complex (99%), and 12th cranial nerve (31%), as well as superior cerebellar artery (79%), anterior inferior cerebellar artery (AICA) trunk (91.5%), AICA branches (100%), posterior inferior cerebellar artery (PICA) trunk (59.5%), PICA branches (79%), and the vertebral artery (VA) (93.5%). A small number of patients in Group III also had AICA (3.3%), PICA (3.3%), or VA (1.3%) vessels within the tumor itself. CONCLUSIONS: In this study, the authors show the great variation in anatomical location and involvement of neurovascular structures in the CPA. With this knowledge, they present certain technical lessons that may be useful in preserving nerve function during surgery and, in doing so, hope to provide neurosurgeons and neurootologists with valuable information that may help to achieve optimum outcomes in patients.
Adult↗
Laparoscopic treatment of an anterior sacral meningocele. Case illustration.
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Adult↗
The Hunterian Neurosurgical Laboratory: the first 100 years of neurosurgical research.
Modern neurosurgery has long had a strong laboratory foundation, and much of this tradition can be traced to the Hunterian Neurosurgical Laboratory of the Johns Hopkins Hospital. Founded with the basic goals of investigating the causes and symptoms of disease and establishing the crucial role that surgeons may play in the treatment of disease, the Hunterian laboratory has adhered to these tenets, despite the dramatic changes in neurosurgery that have occurred in the last 100 years. Named for the famous English surgeon John Hunter (1728-1793), the Hunterian laboratory was conceived by William Welch and William Halsted as a special laboratory for experimental work in surgery and pathology. In 1904, Harvey Cushing was appointed by Halsted to direct the laboratory. With the three primary goals of student education, veterinary surgery that stressed surgical techniques, and meticulous surgical and laboratory record-keeping, the laboratory was quite productive, introducing the use of physiological saline solutions, describing the anatomic features and function of the pituitary gland, and establishing the field of endocrinology. In addition, the original development of hanging drop tissue culture, fundamental investigations into cerebrospinal fluid, and countless contributions to otolaryngology by Samuel Crowe all occurred during this "crucible" period. In 1912, Cushing was succeeded by Walter Dandy, whose work on experimental hydrocephalus and cerebrospinal fluid circulation led to the development of pneumoencephalography. The early days of neurosurgery evolved with close ties to general surgery, and so did the Hunterian laboratory. After Dandy began devoting his time to clinical work, general surgeons (first Jay McLean and then, in 1922, Ferdinand Lee) became the directors of the laboratory. Between 1928 and 1942, more than 150 original articles were issued from the Hunterian laboratory; these articles described significant advances in surgery, including pioneering research on calcium metabolism by William MacCallum and Carl Voegtlin and seminal preclinical work by Alfred Blalock and Vivian Thomas that led to the famous "blue baby" operation in 1944. With the introduction of the operating microscope in the 1950s, much of the focus in neurosurgical science shifted from the laboratory to the operating room. The old Hunterian building was demolished in 1956. The Hunterian laboratory for surgical and pathological research was rebuilt on its original site in 1987, and the Hunterian Neurosurgical Laboratory was reestablished in 1991, with a focus on novel treatments for brain tumors. The strong tradition of performing basic research with clinical relevance has continued.
Baltimore↗
Long-term visual outcome after nonradical microsurgery patients with parasellar and cavernous sinus meningiomas.
OBJECTIVE: To determine the long-term visual outcome in patients with parasellar and cavernous sinus meningiomas treated with nonradical surgery. METHODS: Retrospective clinical review of 29 patients with parasellar or cavernous sinus meningiomas and visual sensory or ocular motor dysfunction at presentation, all of whom had at least 10 years of follow-up after initial diagnosis and treatment with nonradical surgery. RESULTS: Nineteen of 29 patients had a unilateral or bilateral optic neuropathy at presentation, and 7 patients developed a unilateral or bilateral optic neuropathy during a mean follow-up period of 13.6 years. However, 27 (93%) of 29 patients retained vision of 20/40 or better in at least one eye, and 14 patients (48%) retained vision of 20/40 or better in both eyes. New ocular motility deficits developed in 3 (10%) of 29 patients during the follow-up period. CONCLUSION: Radical surgery is not required to achieve long-term useful visual function for patients with parasellar or cavernous sinus meningiomas.
Adolescent↗
The operating room of the future.
The operating room of the future will be designed to have peri-operative integration of all imaging capabilities. Pre-operative planning will become increasingly important, as will integrated intra-operative neuro-navigation. The operative work space will be redesigned to have robotic capabilities. Operating rooms will be isolated. Self-contained modular and robotic monitoring will become remote through improved sensors. The operating microscope will disappear. Light and magnification will be supplied by means other than optical microscopes.
Biomedical Engineering↗