Intracranial Neurosurgery Research Articles

Postoperative intracranial neurosurgery infection rates in North America versus Europe: A systematic analysis

Postoperative wound infection (PWI) after intracranial neurosurgery remains a significant worldwide problem, resulting in substantial morbidity/mortality if not combatted quickly and energetically. Although the danger of PWI is universally recognized, the reported incidence of PWI after intracranial neurosurgery remains variable, ranging from 1% to 8% in published series. The impact of geography on this reported variability has not been previously investigated. To address this issue, published comprehensive intracranial neurosurgery series were reviewed, segregating findings geographically between North American and European series. A comprehensive literature search was conducted using the Entrez gateway of the PubMed database. Studies conducted in North America and Europe reporting the incidence of PWI after intracranial neurosurgery were subjected to a thorough review. Data from studies meeting inclusion criteria (minimum of 500 cases with no systematic exclusion of procedures) were categorized by origin (North American/European) and design (retrospective/prospective). Recorded incidences were then compared using chi(2) analysis, and estimates of the relative risk of PWI were calculated. Seven studies (4 North American, 3 European) met all of the inclusion criteria, with a 2.6-fold greater PWI incidence reported in the European studies (P < .001). The relative risk of PWI for Europeans versus North Americans per operative case was 2.60. PWI after intracranial neurosurgery was nearly 3 times more likely in European versus North American studies. These findings should be considered by clinicians when estimating the risks of intracranial neurosurgery, and highlight the need for future prospective studies to provide evidence-based explanations for these differences.

Intracranial Surgery With a Compact, Low-Field-Strength Magnetic Resonance Imager

Intraoperative magnetic resonance imaging (iMRI) has been a reality for more than a decade. As technology has begun to mature, the focus on practicality and user-friendliness has sharpened. In addition, the need for well-designed and well-executed outcome studies remains so that expensive new instruments such as iMRI can be justified. We present our experience with the PoleStar system, a compact, low-field-strength iMRI designed to make intraoperative imaging a routine component of intracranial neurosurgery. The advantages and limitations of this approach are discussed in the context of different clinical applications.

Advantageous effects of dexmedetomidine on haemodynamic and recovery responses during extubation for intracranial surgery

The anaesthetic method for intracranial neurosurgery must provide haemodynamic stability on emergence and allow early evaluation of the neurological status. In this study, we examined the effects of the alpha-2 agonist dexmedetomidine given at the end of the procedure to prevent hyperdynamic responses during extubation and to allow a comfortable and high-quality recovery. Forty ASA I-III patients, aged between 18 and 75 yr, having elective intracranial surgery, were divided into two random groups. Standard procedures and drugs were used for monitoring, induction and maintenance. Isoflurane was reduced by 50% 5 min before the end of the surgery, and in Group I dexmedetomidine 0.5 microg kg(-1) and in Group II 20 mL of 0.9% NaCl were administrated intravenously over 60 s. Systolic, diastolic and mean arterial pressures, and heart rate were recorded before intravenous administration and also at 1, 3 and 5 min after administration, 1 min before extubation, during extubation, 1, 3, 5, 10, 15, 20 and 30 min after extubation. Duration of extubation and recovery were noted, and the quality of extubation was evaluated on a 5-point scale. Mean arterial pressure and heart rate were significantly higher in Group II than in Group I (P < 0.01). There were no statistically significant differences between groups regarding the duration of extubation and recovery (P > 0.05). Extubation quality score of all the patients were 1 in Group I and in Group II, the quality scores were 1 for 35%, 2 for 45% and 3 for 20% of the patients (P < 0.001). None of the patients in Group I and Group II showed respiratory depression, nausea or vomiting. Without interfering in recovery time, dexmedetomidine 0.5 microg kg(-1) administered 5 min before the end of surgery stabilizes haemodynamics, allows easy extubation, provides a more comfortable recovery and early neurological examination following intracranial operations.

Muscle enzyme elevation after elective neurosurgery

Serum creatine kinase and myoglobin elevation has been described involving muscle manipulation after surgery and also after bariatric, urologic and gynaecologic procedures. It encompasses a wide range of severity, reflecting in the worst cases true rhabdomyolysis. We occasionally noted creatine kinase elevations after intracranial neurosurgery, an occurrence that has not yet been described. To assess whether the issue of postoperative muscle enzyme elevation is relevant to neurosurgery, we prospectively measured serum creatine kinase and myoglobin in a series of neurosurgical patients submitted to craniotomy. We studied 30 patients aged 22-69 yr submitted to craniotomy. Blood samples were taken prior to the procedure, at the end of anaesthesia and on the first, second and third postoperative days. Blood was checked for creatine kinase, myoglobin, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine and serum electrolytes. We recorded the patient's age, sex, height, weight and body mass index. Throughout surgery, we recorded the highest and the lowest body temperature and sampled the mean arterial pressure at 5 min intervals. We performed backwards stepwise logistic regression analysis to identify the elements that best correlate with the development of cell muscle damage. On the first postoperative day creatine kinase peaked from baseline (305 (107-1306) UI L(-1) vs. 59 (42-94) UI L(-1); P < 0.001) while myoglobin rose significantly from baseline to the end of surgery (70 (42-147) ng mL(-1) vs. 36 (3044) ng mL(-1); P = 0.002). Logistic regression showed that length of surgery was the only factor clearly influencing peak creatine kinase (P < 0.001; R2 0.7) and myoglobin (P = 0.011; R2 0.41) concentration. Creatine kinase and myoglobin elevation may occur after intracranial neurosurgery. In our series, length of surgery was a risk factor.

Unusual Intracranial Lesions Managed with Skull Base Neurosurgical Approaches—Why We Must Continually Emphasize Cerebrovascular/Skull Base Training in Neurological Surgery

Introduction: Neurosurgery in the United States has evolved mainly into surgery for spinal fusion, primarily because of economic incentives. Contemporaneously, the introduction of “minimally invasive” treatments such as radiosurgery and endovascular therapy has resulted in a marked de-emphasis on the microsurgery of complex intracranial diagnoses. Statements rife in the current neurosurgical environment such as “the death of cerebrovascular neurosurgery” are unjustified and underscore a need to further emphasize cerebrovascular/skull base training. This resurgence of emphasis would facilitate the appropriate continuing treatment of complex intracranial diagnoses that present in everyday clinical scenarios in the neurosurgical care of the populations being served. Methods: The author presents the microneurosurgical management of 13 unusual intracranial diagnoses with skull base microsurgical approaches ranging the gamut from cerebellomedullary angle arachnoid cyst to bilateral distal anterior cerebral artery aneurysms. Results: Five major intracranial approaches and variations were used in this clinical series: pterional transylvian approach with skull base modifications, anterior and posterior interhemispheric approaches, subtemporal approach with modifications, and far lateral transcondylar approach which subsumes other posterior fossa approaches. Conclusions: Adequate exposure and control of hemorrhage are the major tenets of any intracranial operation. The author contends that technical mastery of the aforementioned five major intracranial approaches satisfactorily addresses most if not all conditions likely to be encountered by a neurosurgeon in intracranial neurosurgical practice. It is easy to abdicate responsibility of “difficult” intracranial cases to minimally invasive and “novel” therapeutic modalities. However, under such circumstances, a highly variable fraction of patients will receive suboptimal care, particularly based on current trends in neurosurgery in the United States. Future progress in intracranial neurosurgery requires a revival in enthusiasm and commitment to push the frontiers of surgical progress by further emphasizing the critical elements of cerebrovascular/skull base neurosurgery.

Application of computer-assisted design in craniofacial reconstructive surgery using a commercial image guidance system

The technology of digital image guidance systems has transformed many aspects of neurosurgery, including intracranial tumor surgery, functional neurosurgery, and spinal surgery. Despite the central role of imaging studies in diagnosis and treatment planning, intraoperative image guidance has so far had very limited application to the surgical correction of craniofacial deformities, particularly those associated with craniosynostosis. The authors report an example of the marriage of computer-assisted design methods to a commercially available neurosurgical image-guidance system in the treatment of a case of anterior plagiocephaly due to unilateral coronal synostosis. They discuss the steps that must yet be taken to make this technology applicable to the management of craniosynostosis in infants.

Fast forwarding: the evolution of neurosurgery

Despite the major social and economic reorganization of medical practice that has taken place during the past 40 years, neurosurgery-the most fascinating specialty in all of clinical medicine-has grown and prospered. Today, this specialty is poised for an era of spectacular advancement and improvement in care; however, significant problems with the potential to retard this growth face neurosurgery. Among these problems is the medical liability situation, which has the potential to destabilize neurosurgical practices and the current health care delivery system. Other issues facing neurosurgery include the potential for loss of the unique nature of the specialty through a conversion to shift-worker surgeons and increasing reliance on profit-seeking institutions for financial stability and liability protection. Lifestyle choices are of growing importance and currently discourage women from entering the field. With a growing knowledge base, there is the recognition that it may not be possible for most individuals to master all aspects of the specialty. There is continued confusion about manpower needs. In addition, some neurosurgeons are choosing to practice in ways that fail to meet the neurosurgeon's obligations to society. There is a growing number of neurosurgeons who dislike providing trauma coverage and there is the potential for some neurosurgeons to give up intracranial neurosurgery. The author believes that it is not competition that will improve the delivery of neurosurgical care and allow for continued growth, but cooperation, and that it will be possible to alleviate many of our problems through increased regionalization of neurosurgical care delivery. This proposal has the potential to promote the formation of neurosurgical teams, ameliorate the problem of physician fatigue, allow greater development of subspecialty skills, and ease the burden of trauma call. It should allow satisfactory solutions to lifestyle considerations and encourage more women to enter the field of neurosurgery. Such a transformation would encourage advances in care to be brought rapidly into the clinical setting and allow neurosurgery to be practiced at the very highest level.

Preoperative prediction of severe postoperative pain

We developed and validated a prediction rule for the occurrence of early postoperative severe pain in surgical inpatients, using predictors that can be easily documented in a preoperative setting. A cohort of surgical inpatients ( n=1416) undergoing various procedures except cardiac surgery and intracranial neurosurgery in a University Hospital were studied. Preoperatively the following predictors were collected: age, gender, type of scheduled surgery, expected incision size, blood pressure, heart rate, Quetelet index, the presence and severity of preoperative pain, health-related quality of life the (SF-36), Spielberger's State–Trait Anxiety Inventory (STAI) and the Amsterdam Preoperative Anxiety and Information Scale (APAIS). The outcome was the presence of severe postoperative pain (defined as Numeric Rating Scale ≥8) within the first hour postoperatively. Multivariate logistic regression in combination with bootstrapping techniques (as a method for internal validation) was used to derive a stable prediction model. Independent predictors of severe postoperative pain were younger age, female gender, level of preoperative pain, incision size and type of surgery. The area under the receiver operator characteristic (ROC) curve was 0.71 (95% CI: 0.68–0.74). Adding APAIS scores (measures of preoperative anxiety and need for information), but not STAI, provided a slightly better model (ROC area 0.73). The reliability of this extended model was good (Hosmer and Lemeshow test p-value 0.78). We have demonstrated that severe postoperative pain early after awakening from general anesthesia can be predicted with a scoring rule, using a small set of variables that can be easily obtained from all patients at the preoperative visit. Before this internally validated preoperative prediction rule can be applied in clinical practice to support anticipatory pain management, external validation in other clinical settings is necessary.

顔面けいれんのＤｏｘｏｒｕｂｉｃｉｎ選択的神経ブロック術

Objective: To describe our experience with adriamycin (ADM) selective chemical rhizotomy of facial nerves in a patient with hemifacial spasm (HFS) who refused neuro-vascular decompression surgery. This unique technique was less invasive than intracranial neuro-surgery. It was possible to perform a permanent nerve block under local anesthesia.Case report: The patient, a 73-year-old female, had difficulty opening her left eye due to HFS. After treatment with antiepileptic medicine (carbamazepine) was ineffective, the patient received selective intraneural injections of ADM under local anesthesia. One week after the surgery, the spasms had disappeared completely and slight muscle weakness was observed. No major complications were caused by this procedure and no recurrence of spasms was observed two years after the surgery.Main outcome: It is thought that recurrence of HFS should be observed after simple neurotomy due to re-growth of nerve fibers. However, this did not occur after selective ADM chemical rhizotomy of facial nerves. This method clearly differs from previously used methods of simple neurotomy because simple neurotomy does not cause severe destructive change in the facial motor nucleus.Conclusion: We conclude that selective facial nerve chemical rhizotomy with ADM under local anesthesia may be effective in treating a subgroup of patients with HFS, especially elderly patients and those in high risk groups for general anesthesia and intra cranial neuro-vascular decompression surgery.

Experiences with Cranial Neuronavigation in Pediatric Neurosurgery

Frameless, infrared-based neuronavigation (Surgical Microscope Navigator^® and Surgical Tool Navigator^®) was applied to intracranial neurosurgery in 22 children and infants (age range 7 months to 16 years). Predominant diagnoses were tumor and hydrocephalus (including multiloculated forms); the surgical procedures were open microneurosurgery in 10 cases and neuroendoscopy in 12 patients. There were no principal technical problems even in very young infants. Surgical and clinical results were satisfying in all cases. Neuronavigation proved to be particularly helpful in targeting deep-seated processes and in guiding neuroendoscopy in cases of multiloculated hydrocephalus or small ventricles.

Prevention and treatment of venous thromboembolism after major trauma

In prospective studies the incidence of deep venous thrombosis, documented by venography, is between 35% and 63% in patients with major trauma. Five independent risk factors for deep vein thrombosis have been identified in these patients: older age, fracture of the femur or tibia, surgery, spinal cord injury and blood transfusion. Mechanical antithrombotic methods and low-dose unfractionated heparin administered subcutaneously moderately decrease the risk of venous thromboembolism but are less effective than a fixed dose of subcutaneous unmonitored low molecular weight heparin. Prophylaxis with oral anticoagulants (International Normalized Ratio 2.0-3.0) is also effective but is much less used because of the bleeding risk. This is particularly the case in patients with intracranial neurosurgery and acute spinal cord injury. Only a few clinical studies have evaluated the treatment of venous thromboembolism in patients with major trauma. If the condition of a patient with major injury allows, the treatment of venous thromboembolism recommended after hip replacement is cautiously applied.

The state of the art of neuronavigation with frameless stereotaxy in intracranial neurosurgery

Various localizing mechanisms for intraoperative navigation with frameless stereotaxy have been developed, including proprioceptive arms, freehand probes with infrared optical tracking systems, and integrated microscope/stereotactic systems that map the microscope's focal point. During a 5-year period, 1,212 procedures were performed on 1,155 patients using five navigational devices, and the accuracy and clinical performance of the systems were compared. Operative pathology included 193 gliomas, 128 convexity meningiomas, 117 skull-base tumors, 113 epilepsy operations, 106 cavernous malformations, 65 arteriovenous malformations, 6 aneurysms, 25 acoustic neuromas, 25 ventriculoperitoneal shunt procedures, 45 metastases, 338 other or unspecified primary brain tumors, and 51 miscellaneous lesions. The proprioceptive arm was used in 1,112 procedures (mean error, 1.86 mm); the freehand probe (1-dimensional cameras) was used in 29 procedures (mean error, 1.72 mm); the freehand probe (2-dimensional cameras) was used in 40 procedures (mean error, 2.64 mm); the MKM microscope system (Carl Zeiss, Thornwood, NY) was used in 16 procedures (mean error, 3.08 mm); and the SMN microscope system (Carl Zeiss) was used in 15 procedures (mean error, 2.30 mm). According to a survey of performance characteristics and surgeons' preferences, the proprioceptive arm system had the best apparatus, computer software, tracking mechanism, and display. It was accurate, reliable, and the easiest of the five systems to use. Freehand systems are hampered by tracking interference, and integrated microscope systems are still in the early stages of development.

Repair of Cranial Nerves During Intracranial Neurosurgery

Repair of Cranial Nerves During Intracranial Neurosurgery

Fisher CT and Hunt-hess grades: Relationship with neuropsychological performance following intracranial aneurysm neurosurgery

Fisher CT and Hunt-hess grades: Relationship with neuropsychological performance following intracranial aneurysm neurosurgery

Fisher CT and Hunt-hess grades: Relationship with neuropsychological performance following intracranial aneurysm neurosurgery

Fisher CT and Hunt-hess grades: Relationship with neuropsychological performance following intracranial aneurysm neurosurgery

Transcutaneous carbon dioxide measurement after craniotomy in spontaneously breathing patients.

The purpose of this study was to determine the incidence of postoperative hypercarbia in patients undergoing intracranial neurosurgery. Postoperative hypercarbia is a well-recognized cause of postoperative morbidity. Sixty-four patients undergoing craniotomy were monitored in the first 36 postoperative hours using transcutaneous CO2 monitoring. We collected and analyzed demographic data, complete medical histories and examinations, and details of surgery, anesthesia, and postoperative progress. The accuracy of the transcutaneous CO2 monitoring was evaluated by comparison with arterial blood gas CO2. The "TINA" TCM3 Transcutaneous CO2 Monitor (Radiometer, Copenhagen, Denmark) was used. Thirty-nine patients (61%) developed no hypercarbia. Nineteen patients (30%) developed mild to moderate hypercarbia (46-59 mm Hg) and six patients (9%) developed severe hypercarbia (60 mm Hg or greater). Statistically significant differences were observed between the severely hypercarbic group and the other two groups combined, as follows: a higher incidence of preoperative and postoperative seizures, a lower average postoperative Glasgow Coma Scale score, a higher incidence of reintubation and ventilation, and a higher degree of intraoperative brain disturbance. Analysis of transcutaneous CO2 measurements and time-matched arterial blood gas CO2 measurements revealed an acceptable accuracy of the transcutaneous method. this study demonstrates that, in routine neurosurgical practice, a subgroup of patients are at risk of developing postoperative hypercarbia, which may be more common than is generally recognized and will not usually be detected by routine postoperative monitoring. Transcutaneous CO2 monitoring is a useful technique that may impact management decisions.

Enalaprilat in the treatment of hypertension and heart failure in critical care

Abstract: Neurosurgical patients are particularly vulnerable to uncontrolled hypertension. If the patient has an unclipped cerebral arterial aneurysm, sudden increases in arterial pressure, as may be induced by laryngoscopy and tracheal intubation, may lead to rupture or rebleeding. During the immediate postoperative period after cerebrovascular surgery and intracranial neurosurgery, blood pressure elevation may lead to postoperative hemorrhage and cerebral edema.Left ventricular (LV) dysfunction is common in acute myocardial infarction (AMI). After open heart surgery, LV dysfunction may follow a perioperative AMI or mobilization of peripheral edema. Preceding ischemic cardiomyopathy and a stunned or hibernating myocardium may predispose to postoperative heart failure. In severe forms of heart failure, conventional therapy with inotropes, nitrates and diuretics may prove inadequate, and there is a need to further reduce raised preload and afterload.The present series of studies was carried out in order to assess the effects of pharmacological inhibition of angiotensin converting enzyme (ACE) on the hemodynamics, systemic oxygenation and hormonal regulation of the blood circulation in patients subjected to anesthesia due to neurosurgery or intensive care due to neurosurgery or heart failure complicating AMI or open heart surgery. Oral enalapril premedication or intravenous (i.v.) enalaprilat was either compared to inert placebo or used in five before‐after designed studies with a total of 40 neurosurgical patients and 26 heart failure patients.Oral enalapril premedication (0.1 mg/kg) was effective in preventing a blood pressure increase in response to tracheal intubation in patients subjected to cerebrovascular surgery. At a dose of 0.015 mg/kg, i.v. enalaprilat effectively controlled the postoperative hypertension of patients subjected to intracranial surgery. In patients with heart failure complicating AMI or open heart surgery, the addition of i.v. enalaprilat to conventional therapy (median doses 0.3 mg, 0.9 mg, and 2.0 mg in the three studies) relieved left ventricular filling pressure while maintaining cardiac function and systemic oxygenation. Further, enalaprilat had potentially beneficial hormonal effects in patients with severe heart failure, e.g. by lowering plasma levels of endothelin.Thus, ACE inhibition may expand our armamentarium of drugs to treat hypertension and heart failure in the intensive care unit and to prevent hypertension associated with tracheal intubation.

Craniotomy guidance using a stereo-video-based tracking system.

In open intracranial neurosurgery, it is desirable to minimize exposure and to approach the target in the most accurate way possible. The VISLAN system described here employs a completely passive hand-held locator which is tracked by a video system and does not require a mechanical linkage nor cables. The system also tracks easily recognizable, constant, anatomical landmarks of the patient. By this means the initial registration of pre-operative imaging and the detection of, and correction for, patient movement can be accomplished. High-resolution MRI segmented interactively is used to define external surface and brain anatomy. Thus, a pre-operative patient representation (POPR) is planned. During the surgical procedure the patient's head is illuminated by structured light and stereo-video pictures obtained from two television cameras mounted above the head. The system is calibrated and registered with the POPR using a chamfered matching algorithm. The locator is also tracked in space by the video system, and its tip position shown in relation to the POPR on the video monitor.

Intracranial neurosurgery guided by functional imaging

Neurosurgery on eloquent cortex entails important risks of functional deficits complicating aggressive lesion resection. In this study, advanced biomagnetic functional imaging of somatosensory and motor cortex combined with surface rendered magnetic resonance imaging displays including vascular anatomy were used in conjunction with a new nonintrusive intraoperative guided instrumentation system to resect a tumor in eloquent cortex. Intraoperative verification of the accuracy of pre-operative motor localization demonstrated highly accurate results comparing direct stimulation and noninvasive presurgical mapping. The applicability of surface rendered combined functional and anatomic maps of cortex is directly evident on comparison of preoperative computer images and intraoperative pictures. This combination of new technologies has a significant potential for reduced risk and improved outcome in neurosurgery of eloquent cortex.

Minimally Invasive Surgery: Neurosurgery

The introduction of minimally invasive techniques has greatly improved results for intracranial neurosurgery. Stereotaxy and improved imaging techniques have reduced surgical trauma by allowing surgeons to plan the least damaging route to operative sites and by increasing surgical precision. Stereotaxy has also allowed brain biopsies to be taken from sites such as the brain stem, which were rarely sampled before because free hand biopsy was so dangerous. Brain tumours can now be treated by interstitial radiotherapy--stereotactic insertion of catheters into the lesion for loading of radioactive iodine--or radiosurgery--focusing of intense beams of radiation on lesions without needing surgical incisions. Endoscopic neurosurgery can be used to reach cavities such as the ventricular system or cystic tumours. With interventional neuroradiology fine catheters can be introduced into most vessels in the cranium for embolisation or dilatation. The development of augmentative functional neurosurgery means that movement disorders, epilepsy, and intractable pain can be treated with implanted neurostimulating electrodes. Future developments will probably include frameless stereotaxy, when the rigid attachment of stereotactic apparatus to the patient's head can be dispensed with, and at least partial automation of procedures such brain biopsy.