visit neursurgery NEUROSURGERY October 1996 Vol. 39, No. 4 Abstracts ---------------------------------------------------------------------------- The History of Spinal Biomechanics Abhay Sanan, M.D., Setti S. Rengachary, M.D. Department of Neurosurgery, University of Minnesota Hospital System, Minneapolis, Minnesota The history of spinal biomechanics has its origins in antiquity. The Edwin Smith surgical papyrus, an Egyptian document written in the 17th century BC, described the difference between cervical sprain, fracture, and fracture-dislocation. By the time of Hippocrates (4th century BC), physical means such as traction or local pressure were being used to correct spinal deformities but the treatments were based on only a rudimentary knowledge of spinal biomechanics. The Renaissance produced the first serious attempts at understanding spinal biomechanics. Leonardo da Vinci (14521519) accurately described the anatomy of the spine and was perhaps the first to investigate spinal stability. The first comprehensive treatise on biomechanics, De Motu Animalium, was published by Giovanni Borelli in 1680, and it contained the first analysis of weight bearing by the spine. In this regard, Borelli can be considered the "Father of Spinal Biomechanics." By the end of the 19th century, the basic biomechanical concepts of spinal alignment and immobilization were well entrenched as therapies for spinal cord injury. Further anatomic delineation of spinal stability was sparked by the anatomic analyses of judicial hangings by Wood-Jones in 1913. By the 1960s, a two-column model of the spine was proposed by Holdsworth. The modern concept of Denis' three-column model of the spine is supported by more sophisticated testing of cadaver spines in modern biomechanical laboratories. The modern explosion of spinal instrumentation stems from a deeper understanding of the load-bearing structures of the spinal column. (Neurosurgery, 39:657669, 1996) Key words: Biomechanics, Borelli, Hanging, Hippocrates, History, Spinal devices, Spinal injury, Spine ---------------------------------------------------------------------------- Complications Resulting from Saphenous Vein Patch Graft after Carotid Endarterectomy Yoshihiro Yamamoto, M.D., David G. Piepgras, M.D., W. Richard Marsh, M.D., Fredric B. Meyer, M.D. Department of Neurological Surgery, Mayo Clinic and Mayo Foundation, Rochester, Minnesota OBJECTIVE: Reducing surgical risks to the minimum in carotid endarterectomy has become crucial, especially with the results of recent clinical trials extending indications to asymptomatic patients. The use of the saphenous vein patch graft (SVPG) has been suggested to reduce early postoperative thrombosis and cerebral infarct as well as late recurrent stenosis. However, the exact risks and complications involved in this technique are not known. METHODS: During a 23-year period (19721994), 2888 carotid endarterectomies with SVPG for primary carotid stenosis were performed by the Neurosurgical Cerebrovascular Service at the Mayo Clinic. The data from all patients were retrospectively analyzed, emphasizing postoperative complications related to SVPG. RESULTS: There were five postoperative vein ruptures (0.17%), four cases of aneurysm formation, and three cases of deep infection necessitating surgical intervention. The vein patch ruptured in one male patient and four female patients (mean age, 69 yr). All ruptures occurred within 4 days of the primary operation, including two during the first 24 hours. All patients with rupture underwent emergency surgery and were found to have intact suture lines and tears in the middle of the grafts. Two patients recovered without deficits, one suffered major disability, and the other two died. Aneurysm of the patch developed in two male patients and two female patients (mean age, 71 yr). All of the patients developed painless pulsatile neck masses 1 to 9 years after the initial surgery; two also had recurrent ischemic symptoms. All of the patients with aneurysms underwent surgical correction without consequences. CONCLUSION: Although the benefit of routine use of SVPG in carotid endarterectomy is still the focus of debate, this analysis showed that its use adds a small but definite risk of serious complications related to inherent weakness of the venous tissue. If a surgeon chooses to use a patch graft, our recommendation is for use of a synthetic material rather than vein. (Neurosurgery 39:670676, 1996) Key words: Carotid aneurysm, Carotid endarterectomy, Collagen-impregnated dacron, Saphenous vein patch graft, Vein patch rupture ---------------------------------------------------------------------------- Occult Cerebrovascular Malformations after Irradiation Eugenio Pozzati, M.D., Felice Giangaspero, M.D., Federica Marliani, M.D., Nicola Acciarri, M.D. Department of Neurosurgery and Services of Pathology and Neuroradiology, Bellaria Hospital, Bologna, Italy OBJECTIVE: It has recently been found that patients receiving cerebral irradiation can develop hemorrhagic dysangiogeneses simulating occult vascular malformations. To analyze this connection, we report on five patients with occult cerebrovascular malformations occurring after "standard" or focused irradiation performed for brain tumors in four patients and for a deep-seated cavernous angioma in one patient. METHODS: All lesions were within the radiation ports. The time interval between irradiation and the detection of the occult vascular malformations varied from 3 to 9 years; the ratio of female to male patients was 4:1. Four patients were <15 years old when first irradiated. Four patients presented with acute symptoms (headache, vomiting, focal signs) and one was asymptomatic when the lesions were first detected. Serial magnetic resonance imaging scans were available in four patients and a computed tomographic scan in the other patient. RESULTS: The initial appearance was that of a hypointense T1T2 focus; magnetic resonance imaging then revealed focal or multifocal T1 hyperintensity and T2 mixed signal intensity followed by a late ring of decreased signal intensity. Four patients were operated on and one was under neuroradiological monitoring. Histological features of these lesions included clusters of closely packed vascular spaces resembling cavernous malformations sometimes associated with a thrombosed thick-walled vein with intense hemosiderin deposition and fibroblastic proliferation; telangiectasic changes were also seen in the adjacent brain. CONCLUSION: Increased awareness of occult cerebrovascular malformations is necessary, because their occurrence is not infrequent and they have hemorrhagic potential. Children receiving cerebral irradiation are at greater risk of this complication. (Neurosurgery 39:677684, 1996) Key words: Cavernous angioma, Hemorrhage, Infancy, Magnetic resonance imaging, Occult vascular malformation, Radiation therapy ---------------------------------------------------------------------------- Intracranial Aneurysms and Cervicocephalic Arterial Dissections Associated with Congenital Heart Disease Wouter I. Schievink, M.D., Bahram Mokri, M.D., David G. Piepgras, M.D., Adriana C. Gittenberger-de Groot, Ph.D. Departments of Neurologic Surgery (WIS, DGP) and Neurology (BM), Mayo Clinic, Rochester, Minnesota, and Department of Anatomy and Embryology (ACG-dG), University of Leiden, Leiden, The Netherlands OBJECTIVE: The number of patients with congenital heart disease who survive to adolescence and adulthood continues to increase. We review our experience with noninfectious intracranial aneurysms and cervicocephalic arterial dissections in patients with congenital heart disease, expanding the clinical spectrum of the cerebrovascular abnormalities that may be encountered in this group of patients. METHODS: All patients with congenital heart disease and intracranial aneurysms or cervicocephalic arterial dissections, who were evaluated at the Mayo Clinic between 1969 and 1992, were identified. RESULTS: Congenital heart disease was diagnosed in 3 (8%) of 36 children with intracranial aneurysms, in 5 (0.3%) of 1994 adults with intracranial aneurysms, in 1 (4%) of 25 children with cervicocephalic arterial dissections, and in 5 (2%) of 250 adults with cervicocephalic arterial dissections. The mean age of the 14 patients was 32 years (range, 1358 yr). The congenital heart disorders consisted of complex cardiac anomalies in three patients (truncus arteriosus, transposition of the great arteries, and tricuspid atresia in one patient each), pulmonic valve or arterial stenosis in two patients, aortic coarctation in four patients, and bicuspid aortic valve in five patients. Only one patient had an intracranial aneurysm and coarctation of the aorta. CONCLUSION: Individuals with a variety of congenital heart disorders may be at an increased risk of intracranial aneurysm development and cervicocephalic arterial dissection, particularly in adolescence. The muscular arteries of the head and neck are derived from neural crest cells and the neural crest is also of major importance in early cardiac development, suggesting that an abnormality of the neural crest may be the common pathogenetic factor explaining this association. (Neurosurgery 39:685690, 1996) Key words: Aneurysm, dissecting; Cerebral aneurysm; Cerebrovascular disease; Coarctation of the aorta; Congenital heart disease; Neural crest ---------------------------------------------------------------------------- The Beaten Copper Cranium: A Correlation between Intracranial Pressure, Cranial Radiographs, and Computed Tomographic Scans in Children with Craniosynostosis Gerald F. Tuite, M.D., Jane Evanson, F.R.C.R., W.K. Chong, M.D., Dominic N.P. Thompson, F.R.C.S., William F. Harkness, F.R.C.S., Barry M. Jones, F.R.C.S., Richard D. Hayward, F.R.C.S. The Craniofacial Unit (GFT, DNPT, WFH, BMJ, RDH) and Department of Radiology (JE, WKC), Great Ormond Street Hospital for Children, London, England OBJECTIVE: The beaten copper appearance of the cranium, as well as other cranial radiographic and computed tomographic findings in children with craniosynostosis, is often interpreted by clinicians as evidence of elevated intracranial pressure (ICP). However, a correlation between radiological findings and ICP measurements has not been previously demonstrated, and their usefulness in detecting elevated ICP has not been defined. METHODS: To address those issues, 123 children with craniosynostosis who had cranial radiographs and ICP monitoring were studied. To assess the specificity of certain radiological findings to patients with craniosynostosis, cranial radiographs of patients with craniosynostosis were compared to those of age- and sex-matched controls. In patients with craniosynostosis, findings on cranial radiographs were compared to computed tomographic scans of the brain. Radiographic findings were then correlated with ICP measurements obtained while the patient was sleeping, which was measured using a Camino fiberoptic ICP monitor (Camino Laboratories, San Diego, CA). All radiographs were independently analyzed by two radiologists who were blinded to clinical and ICP data. RESULTS: A diffuse beaten copper pattern, erosion of the dorsum sella, and suture diastasis were seen more commonly in patients with craniosynostosis than in controls (P < 0.05), but the presence of the beaten copper pattern was no more common in children with craniosynostosis. ICP was greater when a diffuse beaten copper pattern, dorsum sellar erosion, suture diastasis, or narrowing of basal cisterns was present (P < 0.05). CONCLUSION: Although this study demonstrates that some cranial radiographic and computed tomographic findings do correlate with elevated ICP, the sensitivity of radiological methods for detecting elevated ICP is universally low and they are not recommended to screen for elevated ICP in children with craniosynostosis. (Neurosurgery 39:691699, 1996) Key words: Computed tomography, Craniosynostosis, Cranium, Hydrocephalus, Intracranial pressure, Lückenschädel ---------------------------------------------------------------------------- Pericytosis and Edema Generation: A Unique Clinicopathological Variant of Meningioma James C. Robinson, M.D., Venkat R. Challa, M.D., David S. Jones, M.D., David L. Kelly, Jr., M.D. Departments of Neurosurgery (JCR, VRC, DSJ, DLK) and Pathology (VRC), Wake Forest University, Bowman Gray School of Medicine, Winston-Salem, North Carolina OBJECTIVE: We report a group of eight patients with a distinctive histological variant of meningioma that is associated with severe peritumoral edema. The clinical presentation, radiographic findings, and histology of this type of tumor may lead to misdiagnosis as an aggressive or malignant process. METHODS: We reviewed the histology from patients who had removal of meningiomas performed in our institution between 1978 and 1992. Tumors having abnormal proliferation of cells in the intramural vascular spaces were selected for study; case histories and radiographs were reviewed. Tumor material was subjected to special stains, immunocytochemical examination, and electron microscopy. RESULTS: Several lesions were misread radiographically as being malignant. Patients underwent craniotomy with complete excision of the tumor. All lesions were small (¾3 cm), and no brain invasion, unusual tumor vascularity, or dural sinus involvement was noted in any case. Histologically, the meningioma pattern in each case was meningothelial and benign in appearance. The immunocytochemical and electron microscopic features of the unusual cells in the blood vessel walls are most consistent with their being of pericytic origin. All patients have remained asymptomatic and without evidence of tumor recurrence with follow-up from 3 to 12 years. CONCLUSION: These tumors showed proliferation of pericytes in blood vessel walls and represent a new subtype of meningothelial meningioma. The apparently benign nature of these lesions necessitates their recognition. Characteristic findings of pericytic proliferation associated with edema generation have led us to descriptively term this the PEG variant of meningioma. (Neurosurgery 39:700707, 1996) Key words: Cerebral edema, Meningioma, Pericyte ---------------------------------------------------------------------------- Computed Tomographic Criteria and Survival Rate for Patients with Acute Subdural Hematoma Matthias Zumkeller, M.D., Renate Behrmann, M.D., Hans Egmont Heissler, Dipl. -Ing., Herrmann Dietz, M.D. Neurochirurgische Klinik, Medizinische Hochschule, Hannover, Germany OBJECTIVE: Computed tomographic data from 174 patients with acute subdural hematoma were analyzed statistically to identify parameters that could be evaluated independently of clinical and neurological status to estimate outcome. METHODS: This retrospective study was made necessary by the fact that the patients admitted usually had been treated with intubation, sedation, and artificial ventilation, which precludes neurological examination. RESULTS: In surgically treated patients, the hematoma thickness ranged from 5 to 35 mm and the midline shift was 0 to 33 mm. In 81 patients (46.6%), the hematoma thickness was greater than the midline shift; in 24 patients (13.8%), the hematoma thickness equaled the midline shift; and in 69 patients (39.6%), the midline shift exceeded the hematoma thickness. Of the patients, 52% died after surgery, for 29% we obtained good or satisfying results, and 19% were in poor condition after therapy. The Kaplan-Meier survival analysis proved that the survival rate was only 50% for a hematoma thickness of approximately 18 mm and a midline shift of 20 mm. The survival function dropped markedly for midline shifts of more than 20 mm and converged to 0% for midline shifts of more than 25 mm. If the midline shift exceeded the hematoma thickness by 3 mm, the survival function was 50%; when the midline shift exceeded the hematoma thickness by 5 mm, the survival function was 25%. The Glasgow Outcome Scale scores were correlated significantly with these parameters. The parameters, which are the measured hematoma thickness, the midline shift, and the difference between the hematoma thickness and the midline shift, allow robust/adequate estimation of survival function and outcome for patients suffering from acute subdural hematoma. CONCLUSION: Based on these data, indications for surgery could be assessed by means of video conferencing, i.e., without personal examination of the patients. (Neurosurgery 39:708713, 1996) Key words: Acute subdural hematoma, Coma scale, Computed tomography, Head injury, Midline shift ---------------------------------------------------------------------------- Early Effects of Mannitol in Patients with Head Injuries Assessed Using Bedside Multimodality Monitoring Peter J. Kirkpatrick, F.R.C.S.(S.N.), Piotr Smielewski, M.Sc., Stefan Piechnik, M.Sc., John D. Pickard, M.Chir., Marek Czosnyka, Ph.D. Academic Department of Neurosurgery, Addenbrookes Hospital, Cambridge, England OBJECTIVE: We have employed bedside multimodality methods to assess the influence of a slow (20 min) bolus of hypertonic mannitol on cerebral hemodynamics in comatose patients with head injuries. METHODS: Middle cerebral artery flow velocities (FV) and cortical microcirculatory flows were measured in comatose patients with head injuries after the administration of 200 ml of 20% mannitol. A comparison was made with the effects of an identical bolus of isotonic saline. Fourteen patients with diffuse head injuries and with raised intracranial pressure were selected, and mannitol infusion studies were conducted when clinically indicated (n = 23). Using transcranial doppler and laser doppler flowmetry (LDF), indices of estimated cerebrovascular resistance (eCVR) were calculated for the macro- (eCVR-FV) and micro- (eCVR-LDF) circulation. RESULTS: During mannitol infusion, a significant rise in cerebral perfusion pressure was detected (+10%, P = 0.03) as a result of a fall in intracranial pressure (-21%, P = 0.001). Increases in both FV (+13%, P < 0.001) and LDF (+14%, P = 0.002) occurred only after the administration of mannitol and persisted beyond completion of infusion. The effect on FV and LDF decayed exponentially, with a time constant of 34.0 and 38.0 minutes, respectively, and was independent of the pressure autoregulatory status. There was a tendency for eCVR-FV and eCVR-LDF to decrease. No significant effects resulted from the administration of saline. CONCLUSION: Bedside multimodality monitoring may provide a useful means for assessing the effects of therapy in the comatose patient. The mechanisms by which mannitol reduces intracranial pressure in patients with head injuries are discussed. (Neurosurgery 39:714721, 1996) Key words: Cerebral hemodynamics, Cerebrovascular resistance, Head injury, LDF, Mannitol, TCD ---------------------------------------------------------------------------- Hydrocephalus and Epilepsy: An Actuarial Analysis Joseph H. Piatt, Jr., M.D., Christina Vert Carlson, B.A., B.S., R.N. Department of Surgery (Neurosurgery) and Pediatrics, Oregon Health Sciences University, Portland, Oregon OBJECTIVE: To determine the prevalence of epilepsy among patients with hydrocephalus and to identify risk factors. METHODS: Retrospective chart review at a single institution was conducted. The definition of epilepsy used was long-term administration of antiepileptic drugs (AEDs) for suppression of seizures. Actuarial methodology was used, with initiation of AED therapy as the endpoint of the analysis. RESULTS: Insertion or revision of cerebrospinal fluid (CSF) shunts was performed on 464 patients at the study institution from 1976 through 1989. At the time of initial CSF shunt insertion, 12% of patients had already been treated with AEDs. After the 2nd year, the hazard rate for initiation of AED treatment was a constant 2% per year, and by 10 years after initial shunt insertion the estimated prevalence of AED treatment had risen to 33%. The cause of the hydrocephalus was a strong determinant of the prevalence of AED treatment, but most of the statistical effect of the cause was already manifest at the time of initial CSF shunt insertion. Age of patient at diagnosis of hydrocephalus, burr hole site, number of CSF shunt operations during follow-up, and history of shunt infection were factors that had no detectable association with AED treatment. CONCLUSION: Epilepsy is common among patients with hydrocephalus, and the risk of the development of epilepsy continues indefinitely for those patients. The complications of CSF shunt surgery seem to play a relatively minor role in the development of epilepsy in this patient population. (Neurosurgery 39:722728, 1996) Key words: Antiepileptic drug, Cerebrospinal fluid shunt, Epilepsy, Hydrocephalus, Myelomeningocele, Seizure ---------------------------------------------------------------------------- The Contralateral Transcallosal Approach: Experience with 32 Patients Michael T. Lawton, M.D., John G. Golfinos, M.D., Robert F. Spetzler, M.D. Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, Arizona OBJECTIVE: To demonstrate the usefulness of the contralateral transcallosal approach for resecting lesions located laterally in or adjacent to the lateral ventricle. METHODS: Modifications to the standard ipsilateral transcallosal technique include positioning the head with the midline oriented horizontally, placing the side with the lesion up, and performing the craniotomy and interhemispheric dissection on the contralateral side. This approach avoids a transcortical incision, allows gravity to hold open the interhemispheric fissure, and increases the lateral exposure of the lesion. This approach was used in 32 patients with a variety of lesions, including 6 cavernous malformations, 7 arteriovenous malformations, and 19 tumors of various types. All but three lesions were located on the left side. RESULTS: All six cavernous malformations, all four benign tumors, and four of the seven arteriovenous malformations were resected completely. Malignant tumors were resected subtotally, and three arteriovenous malformations required stereotactic radiosurgery to treat residual deep nidus. There was no surgical mortality. Two patients experienced neurological deterioration. CONCLUSION: The contralateral transcallosal approach can be used to treat a variety of lesions safely and successfully. (Neurosurgery 39:729735, 1996) Key words: Arteriovenous malformations, Cavernous malformations, Contralateral, Surgical technique, Transcallosal approach, Tumor ---------------------------------------------------------------------------- Transfacial Transclival Approach for Midline Posterior Circulation Aneurysms Christopher S. Ogilvy, M.D., Fred G. Barker II, M.D., Michael P. Joseph, M.D., Mack L. Cheney, M.D., Brooke Swearingen, M.D., Robert M. Crowell, M.D. Cerebrovascular Surgery, Neurosurgical Service, Massachusetts General Hospital (CSO, FGB, BS) and Department of Otolaryngology, Massachusetts Eye and Ear Infirmary (MPJ, MLC), Boston, Massachusetts, and The Berkshire Medical Center, Pittsfield, Massachusetts (RMC) OBJECTIVE: To evaluate the use of an anterior, transfacial transclival approach to midline posterior circulation aneurysms in five patients. SURGICAL APPROACH: A skin incision is made on the right side of the nose with subsequent bony and cartilaginous disarticulation of the nasal complex. The nose remains attached along the left side and is reflected laterally. Removal of the nasal septum and bilateral ethmoidectomy, medial maxillectomy (usually bilateral), and opening of the sphenoid yield a large triangular exposure of the anterior clivus. After removal of the clivus with a drill, the vertebral and basilar arteries are exposed through a midline dural opening. RESULTS: The approach provided excellent exposure of basilar artery trunk aneurysms with room available for temporary clip placement in three patients. In a fourth patient, a midline posterior inferior cerebellar artery aneurysm was clipped using this technique. A basilar trunk dissection was treated by proximal basilar occlusion through this exposure in a fifth patient. Although three patients developed transient cerebrospinal fluid leaks with symptoms of meningitis, no permanent neurological morbidity resulted from the use of the approach. CONCLUSION: The transfacial transclival approach to midline aneurysms of the basilar trunk and its branches provided excellent exposure for surgical treatment in five patients. No patient had postoperative palatal dysfunction and cosmetic results were excellent. Cerebrospinal fluid leak and meningitis continue to be the major drawbacks to the use of this approach, although the availability of modern broad-spectrum antibiotics lessens the chance of permanent neurological sequelae. (Neurosurgery 39:736742, 1996) Key words: Basilar artery, Clivus, Pedicled rhinotomy, Posterior circulation aneurysm, Transclival transfacial approach, Vertebral artery ---------------------------------------------------------------------------- Endoscopic Closure of Postsurgical Anterior Cranial Fossa Cerebrospinal Fluid Leaks Timothy F. Kelley, M.D., James A. Stankiewicz, M.D., James M. Chow, M.D., Thomas C. Origitano, M.D., John Shea, M.D. Department of Otolaryngology, Head and Neck Surgery, University of California, Irvine Medical Center, Orange, California (TFK), and Department of Otolaryngology, Head and Neck Surgery, the Loyola Sinus Surgery Center (JAS, JMC), and Department of Neurosurgery, Loyola University Medical Center (TCO, JS), Maywood, Illinois OBJECTIVE: The primary objective of this study is to present an alternative technique to closure of anterior cranial fossa cerebrospinal fluid (CSF) leaks. This study also serves to review our experience with our technique and presents some technical "tricks" we have learned through experience. METHODS: The design of this study is a clinical chart review. The setting is an academic medical center. RESULTS: Eight patients were referred for closure of postsurgical CSF leaks. Seven of eight patients underwent closure with one attempt and closure was achieved after a second attempt in one patient. Follow-up ranged from 1.5 to 4.0 years. There were no complications. No patient developed an acute or delayed episode of meningitis. CONCLUSION: The technique of endoscopic closure of a CSF leak is a safe and effective means for closure of a postsurgical anterior cranial fossa CSF fistula when performed by an experienced operator. (Neurosurgery 39:743746, 1996) Key words: Anterior cranial fossa, Cerebrospinal fluid leak, Endoscopic, Fistula, Treatment ---------------------------------------------------------------------------- Acrylic Cranioplasty Using Miniplate Struts Robert E. Replogle, M.D., Giuseppe Lanzino, M.D., Paul Francel, M.D., Ph.D., Scott Henson, M.D., Kant Lin, M.D., John A. Jane, M.D., Ph.D. Departments of Neurological Surgery (RER, GL, PF, JAJ) and Plastic Surgery (KL), University of Virginia, Charlottesville, Virginia, and Division of Neurosurgery, Albany Medical College, Albany, New York (SH) OBJECTIVE: Cranioplasty using acrylic is a common procedure in patients with cranial defects secondary to trauma, infection, or tumor. The limitations of this technique include poor adherence of the acrylic to surrounding bone and difficulty in achieving a proper cosmetic contour in complicated cranial defects, especially those involving the orbital rim. The authors have been continually developing techniques of cranioplasty. METHODS: Ten consecutive cranioplasties were performed over the past 5 years using this new technique. TECHNIQUE: The authors describe a technique using miniplates as struts to which the acrylic is applied using a "reinforced concrete" principle. RESULTS/CONCLUSION: All patients achieved excellent cosmetic results with no complications. This technique allows contour of the repair site while the acrylic is curing and provides a more resilient resulting prosthesis. (Neurosurgery 39:747749, 1996) Key words: Cranial defect, Cranioplasty, Orbital rim defect ---------------------------------------------------------------------------- Magnetic Resonance Neurography of Peripheral Nerve Lesions in the Lower Extremity Charles Kuntz IV, M.D., Lindsey Blake, M.D., Gavin Britz, M.D., Aaron Filler, M.D., Ph.D., Cecil E. Hayes, Ph.D., Robert Goodkin, M.D., Jay Tsuruda, M.D., Ken Maravilla, M.D., Michel Kliot, M.D. Departments of Neurological Surgery (CK, GB, RG, MK) and Radiology (LB, CEH, KM), University of Washington and Seattle Veterans Administration Medical Center, Seattle, Washington; Division of Neurological Surgery, University of California, Los Angeles Medical Center, Los Angeles, California (AF); and Department of Radiology, University of Utah School of Medicine, Salt Lake City, Utah (JT) OBJECTIVE: We describe the clinical application and utility of high-resolution magnetic resonance neurography (MRN) techniques to image the normal fascicular structure of peripheral nerves and its distortion by mass lesions or trauma in the lower extremity. METHODS: MRN images were obtained using a standard 1.5 Tesla magnet and custom built phased-array coils. Patients were imaged using T1-weighted spin echo without and with gadolinium, T2-weighted fast spin echo with fat suppression, and short tau inversion recovery fast spin-echo pulse sequences. Nine patients were studied, four with peripheral nerve tumors (three neurofibromas and one schwannoma), two with intraneural cysts, and three with traumatic peripheral nerve lesions. Six patients with peripheral nerve mass lesions underwent surgery, thereby allowing MRN images to be correlated with intraoperative and pathological findings. RESULTS: Preoperative MRN accurately imaged the normal fascicular anatomy of peripheral nerves and precisely depicted its relation to tumor and cystic lesions. Increased signal on T2-weighted fast spin-echo and short tau inversion recovery fast spin-echo pulse sequences was seen in the peripheral nerve fascicles of patients with clinical and electrodiagnostic evidence of nerve injury. CONCLUSION: MRN proved useful in the preoperative evaluation and planning of surgery in patients with peripheral nerve lesions. (Neurosurgery 39:750757, 1996) Key words: Cyst, Magnetic resonance imaging, Neurofibroma, Neuropathy, Peripheral nerve, Schwannoma, Trauma, Tumor ---------------------------------------------------------------------------- Evaluation of Hydrocephalic Periventricular Radiolucency by Dynamic Computed Tomography and Xenon-Computed Tomography Hideki Nakano, M.D., Kuniaki Bandoh, M.D., Makoto Miyaoka, M.D., Kiyosi Sato, M.D. Department of Neurosurgery, Fujisawa City Hospital, Fujisawa City, Kanagawa, (HN, KB, MM), and Department of Neurosurgery, Juntendou School of Medicine (KS), Tokyo, Japan OBJECTIVE: A common finding of computed tomography in a case of normal-pressure hydrocephalus (NPH) is periventricular radiolucency (PVL). We analyzed PVL for patients with hydrocephalus, using dynamic computed tomographic and xenon-computed tomographic techniques to differentiate NPH from similar diseases. METHODS: Dynamic computed tomography was evaluated as a method of diagnosing NPH in 14 patients with computed tomographic findings of both PVL and ventricular dilatation. Of the 14 patients, varying degrees of clinical improvement after shunt surgery were observed in 10 (shunt-effective group) but not in the remaining 4 (shunt-ineffective group). The difference in arrival time between PVL and thalamus, the difference in peak time between PVL and anterior cerebral artery, and cerebral blood flow in PVL by xenon-computed tomographic study were analyzed. RESULTS: The difference in arrival time between PVL and thalamus was significantly longer in the effective group than among the remaining patients. There was no significant difference in PVL/cerebral blood flow and the difference in peak time between PVL and the anterior cerebral artery between the two groups. CONCLUSION: Dynamic computed tomographic analysis of the difference in arrival time between PVL and thalamus is useful for diagnosing NPH and predicting response to shunting. (Neurosurgery 39:758763, 1996) Key words: Dynamic computed tomography, Normal pressure hydrocephalus, Periventricular radiolucency, Xenon-computed tomography ---------------------------------------------------------------------------- Bovine Pericardium for Dural Grafts: Clinical Results in 35 Patients John A. Anson, M.D., Erich P. Marchand, M.D. Division of Neurosurgery, University of New Mexico School of Medicine, Albuquerque, New Mexico OBJECTIVE: The United States Food and Drug Administration has recently approved the marketing of bovine pericardium as a dural graft material, but literature reports of this use are limited. Bovine pericardium has been widely used for grafts in cardiac surgery and seems to have suitable properties for use as a dural graft. We report the use of glutaraldehyde-processed bovine pericardium for dural grafts in 35 patients undergoing cranial and craniospinal operations with the objective of providing a clinical assessment of this material and technique. METHODS: This report is a retrospective analysis of 35 patients. All available records were reviewed and information regarding the indication for grafting, graft size, complications, and outcome were collected and analyzed for all patients. RESULTS: Indications for grafting included meningioma resection, posterior fossa craniotomy, Chiari decompression, dural-based metastases, and trauma. Outcomes were good or excellent in 32 patients; the three fair or poor outcomes were not related to surgical closure. In no patient was the dural graft a significant factor in outcome. Bovine pericardium was found to be easily sutured to be watertight using standard suture material. The material is relatively inexpensive and requires no additional incision. It has low antigenicity and toxicity, good strength, and minimal elasticity. CONCLUSION: In this clinical assessment, bovine pericardium was found to be an excellent dural graft material. (Neurosurgery 39:764768, 1996) Key words: Bovine pericardium, Craniotomy, Dura mater, Graft, Meningioma ---------------------------------------------------------------------------- Surgical Anatomy of the Anterior Cervical Spine: The Disc Space, Vertebral Artery, and Associated Bony Structures T. Glenn Pait, M.D., James A. Killefer, M.D., Kenan I. Arnautovic, M.D. Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas (TGP, KIA), and Department of Neurosurgery (JAK), West Virginia University, Morgantown, West Virginia OBJECTIVE: To elucidate the relationships between the neurovascular structures and surrounding bone, which are hidden from the surgeon by soft tissue, and to aid in avoiding nerve root and vertebral artery injury in anterior cervical spine surgery. METHODS: Using six cadaveric spines, we measured important landmarks on the anterior surface of the spine, the bony housing protecting the neurovascular structures in the lateral disc space, and the changes that occur during the discectomy with interbody distraction of the vertebral bodies. The measurements included the distance between the medial borders of the longus colli muscle at the level of each interspace; the width and height of each disc space at the midline; the width and height of the costal process; the distances between the cranial tip of the uncinate process (UP) and the vertebral body (VB) above and from the tip of the UP to the vertebral artery; the anteroposterior diameter or the extent of the disc spaces in the midline; the height at the midpoint of the distracted disc space; the UP-VB distance in distraction; and the width of the visible nerve root. RESULTS: The distance between the medial borders of the longus colli muscles increased in a rostral to caudal direction. The height of the UP was shortest at C4C5 and greatest at C5C6; the width was narrowest at C4C5 and widest at C6C7. The width of the costal process measured from the VB to the anterior tubercle was narrowest at C2C3 and widest at C6C7. The midpoint height of the costal process was smallest at C6C7 and tallest at C4C5 and C5C6. The nondistracted UP-vertebral artery distance was the shortest at C2C3 and longest at C4C5. The nondistracted UP-VB distance averaged 1 mm at C2C3 and C6C7 and 1.5 mm at C4C5. The height of the distracted disc space was shortest at C2C3 and C6C7. The UP-VB distance after distraction was greatest at C4C5. Only at the C2C3 interspace was the nerve always above the process. The vertebral artery entered the foramen transversarium of C6 in all the specimens. CONCLUSION: Although avoiding unfortunate injury is not always possible, understanding the locations and relations among the anatomic features is the only safeguard against unwarranted damage. (Neurosurgery 39:769776, 1996) Key words: Costal process, Longus colli muscles, Uncinate process, Vertebral artery ---------------------------------------------------------------------------- Microsurgical Anatomy of the Infratemporal Fossa as Viewed Laterally and Superiorly Fotios D. Vrionis, M.D., Ph.D., William G. Cano, M.D., Carl B. Heilman, M.D. Department of Neurosurgery, Tufts University School of Medicine and New England Medical Center, Boston, Massachusetts OBJECTIVE: Benign tumors involving the cavernous sinus, trigeminal nerve, and middle cranial fossa occasionally extend to the infratemporal fossa (ITF). In this study, we describe the microsurgical anatomy and dissection of the ITF, as viewed laterally and superiorly. We also describe a new bypass graft to the supraclinoid internal carotid artery using the internal maxillary artery (IMA), which is found in the ITF. METHODS: Twelve cadaver specimens were used. Dissection required zygomatic arch osteotomy, downward displacement of the temporalis muscle, extensive subtemporal craniectomy, and mild elevation of the temporal lobe together with the dura. RESULTS: The anatomic relationships between the lateral and medial pterygoid muscles and the neurovascular bundle of the ITF are demonstrated. The neurovascular bundle contains the IMA, which runs horizontally, and the main branches of the mandibular nerve, which run vertically. The course and anatomic variations of the IMA and inferior alveolar, lingual, auriculotemporal, and buccal nerves are shown. The distal IMA was quite tortuous and, when the artery was straightened, we were able to perform a tension-free in situ IMA graft to the supraclinoid carotid artery in 9 of 12 specimens. CONCLUSION: Knowledge of the anatomy of the ITF is a prerequisite for tumor resection in this area. The IMA may serve as a bypass graft to the supraclinoid internal carotid artery if the cavernous or petrous carotid artery is involved by tumor and needs to be sacrificed. (Neurosurgery 39:777786, 1996) Key words: Bypass graft, Cerebral revascularization, Cranial base surgery, Infratemporal fossa, Maxillary artery, Microsurgical anatomy ---------------------------------------------------------------------------- Functional Anatomic Relationship between Brain Stem Tumors and Cranial Motor Nuclei Nobu Morota, M.D., Vedran Deletis, Ph.D., M.D., Mark Lee, Ph.D., M.D., Fred J. Epstein, M.D. Division of Pediatric Neurosurgery (NM, ML, FJE) and Department of Anesthesiology (VD), New York University Medical Center, New York, New York OBJECTIVE: To identify patterns of cranial motor nuclei (CMN) displacement in cases of intramedullary brain stem tumor, using neurophysiological mapping of motor nuclei on the floor of the fourth ventricle. METHODS: Relationships between tumors and CMN were reviewed in 18 patients with brain stem tumors (seven pontine, nine medullary, and two pontomedullary tumors) and 2 with cervicomedullary junction spinal cord tumors. CMN VII, IX/X, and XII were mapped by applying electrical stimuli over the surgically exposed fourth ventricular floor through a handheld probe and recording electrical activity in the appropriate cranial muscles. RESULTS: Tumors distorted the anatomic location of CMN in repetitive patterns according to tumor site. Three patterns were identified as follows: Type 1, CMN located around the tumor on the floor of fourth ventricle; Type 2, one or more CMN located ventrally to the tumor; Type 3, CMN in original anatomic position. Six of seven patients with pontine tumors showed the Type 1 pattern. Seven of nine patients with medullary tumors showed Type 2, and the other two showed Type 1. Both patients with pontomedullary tumors showed Type 2. One patient with a cervicomedullary junction spinal cord tumor showed Type 1 and the other Type 3, depending on the tumor extension into the fourth ventricle. CONCLUSION: Pontine tumors push the CMN to around the tumor edge, suggesting that precise localization of CMN before tumor resection is necessary to avoid their damage. Medullary tumors grow more exophytically and compress the CMN ventrally. Understanding patterns of CMN displacement can help surgeons establish the surgical plan, minimize risks, and enable safer surgery of brain stem tumors. (Neurosurgery 39:787794, 1996) Key words: Brain stem, Cranial motor nucleus, Fourth ventricle, Mapping, Tumor ---------------------------------------------------------------------------- Response of Spinal Cord Blood Flow to the Nitric Oxide Inhibitor Nitroarginine Patrick W. Hitchon, M.D., Loren J. Mouw, M.D., Thomas N. Rogge, M.S., James C. Torner, Ph.D., Adrienne K. Miller, B.Sc. Department of Surgery, Division of Neurosurgery (PWH, LJM, TNR, AKM), and Department of Preventive Medicine and Environmental Health, Division of Epidemiology (JCT), College of Medicine, The University of Iowa, Veterans Administration Medical Center, Iowa City, Iowa OBJECTIVE: The extent to which nitric oxide (NO) is involved in the modulation of spinal cord blood flow (SCBF) in the uninjured and injured cord is unknown. To elucidate these questions, the following experiments in anesthetized rats were conducted. METHODS: Because NO is an unstable free radical with a half-life of seconds, its role can be understood through the study of the NO synthase inhibitor L-NG-nitroarginine (L-NOARG). L-NOARG was administered intravenously for 30 minutes at a dose of 100 or 500 µg/kg/min in 12 and 10 uninjured animals, respectively. SCBF fluctuations at C7T1 were measured using laser doppler flowmetry. In a second set of 12 rats, L-NOARG (500 µg/kg/min) was administered 10 minutes before spinal cord injury using a modified aneurysm clip at C7T1 and continued for 30 minutes thereafter. RESULTS: In the uninjured animals, L-NOARG was associated with a dose-dependent increase in mean arterial pressure of 20 to 80% above baseline (P = 0.0001), together with a dose-related decrease in SCBF (P = 0.0373). In the injured animals, L-NOARG was associated with a 48% increase in mean arterial pressure. With L-NOARG, the changes in SCBF from baseline after injury were similar to those of noninjured controls (n = 25) and significantly less than injury controls (n = 18) or those receiving phenylephrine (n = 8). CONCLUSION: NO synthase inhibitors, by reducing available NO, cause systemic vasoconstriction and a decrease in SCBF in the uninjured spinal cord. In the injured spinal cord, the administration of L-NOARG results in a redistribution of blood flow with an augmentation in posttraumatic SCBF at the injury site. (Neurosurgery 39:795803, 1996) Key words: L-Arginine analogs, Laser doppler flowmetry, Nitric oxide, Spinal cord blood flow ---------------------------------------------------------------------------- Ultrastructural Evidence for Arteriolar Vasospasm after Spinal Cord Trauma David L. Anthes, M.A., M.D., Elizabeth Theriault, Ph.D., Charles H. Tator, M.D., Ph.D. Canadian Paraplegic Association Spinal Cord Injury Research Laboratory, Playfair Neuroscience Unit, The Toronto Hospital, University of Toronto, Toronto,Ontario, Canada OBJECTIVE: The primary objective of this study was to investigate the potential contribution of vasospasm to the cascade of secondary injury processes after traumatic spinal cord injury. Although ischemic factors have been implicated, in that vessel rupture, compression, and intravascular thrombosis are readily identifiable, vasospasm has been more difficult to detect. METHODS: The sulcal arterioles in the ventral median fissure of the cervical spinal cord from adult rats were quantitatively examined at the ultrastructural level up to 24 hours after compression injury. RESULTS: There were statistically significant changes in the luminal cross-sectional area of sulcal arterioles after spinal cord injury, correlating directly with decreases in length and increases in width of medial smooth muscle cells. A simple mathematical model of postinjury blood flow is presented, suggesting an 80% decrease caused by vasospasm alone. CONCLUSION: Our results clearly implicate vasospasm as a contributing factor to secondary injury processes after traumatic spinal cord injury. (Neurosurgery 39:804814, 1996) Key words: Microcirculatory pathology, Spinal cord injury, Vasospasm ---------------------------------------------------------------------------- Effect of P2-purinoceptor Antagonists on Hemolysate-induced and Adenosine 5'-Triphosphate-induced Contractions of Dog Basilar Artery in Vitro Bogdan Sima, B.A., R. Loch Macdonald, M.D., Ph.D., Linda S. Marton, Ph.D., Bryce Weir, M.D., John Zhang, M.D., Ph.D. Section of Neurosurgery, University of Chicago Medical Center, Chicago, Illinois OBJECTIVE: To test the hypothesis that the vasoactive effects of hemolysate of dog erythrocytes on dog basilar artery in vitro are caused by adenosine 5'-triphosphate (ATP). METHODS: Dog erythrocyte hemolysate was assayed for ATP by high-pressure liquid chromatography. Dog basilar arteries were cut into rings and studied under isometric tension to determine the effects of the P2-purinoceptor antagonists suramin, pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid, and reactive blue 2 on contractions induced by hemolysate, prostaglandin F2alpha (PGF2alpha), Kcl, uridine 5'-triphosphate, and ATP. RESULTS: Dog erythrocyte hemolysate contained 34 µmol/L of ATP. Hemolysate produced concentration-dependent contractions of dog basilar artery. Suramin (100 µmol/L) significantly inhibited contractions to hemolysate, ATP, and uridine 5'-triphosphate but not to PGF2alpha and KCl (P < 0.05). Pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid (100 µmol/L) caused a small but significant reduction of the contractions to hemolysate and did not affect contractions to PGF2alpha and KCl. Reactive blue 2 (30 µmol/L) produced significant inhibition of contractions to hemolysate and PGF2alpha but did not affect contractions to KCl. CONCLUSION: These findings suggest that ATP mediates a smooth muscle contractile response of hemolysate on dog basilar artery. Because erythrocyte cytosol is known to be important in the pathogenesis of vasospasm, these results suggest that ATP may contribute to the vasoconstriction that occurs in vasospasm. (Neurosurgery 39:815822, 1996) Key words: Adenosine 5'-triphosphate, Basilar artery, Canine, P2-purinoceptors, Subarachnoid hemorrhage, Vasospasm ---------------------------------------------------------------------------- Enzyme-linked Immunosorbent Assay Quantification of Cytokine Concentrations in Human Meningiomas Elad I. Levy, B.S., Javier E. Paino, M.D., Prem S. Sarin, Ph.D., Allan L. Goldstein, Ph.D., Anthony J. Caputy, M.D., Donald C. Wright, M.D., Laligam N. Sekhar, M.D. School of Medicine (EIL), Department of Biochemistry and Molecular Biology (JEP, PSS, ALG), and Department of Neurological Surgery (AJC, DCW, LNS), The George Washington University, Washington, District of Columbia OBJECTIVE: To gain insight into the network of cytokine gene expression in the brain tumor microenvironment, we investigated the presence of the following cytokines in freshly excised brain tumors: interleukin (IL)-1beta, IL-2, IL-4, and IL-6. METHODS: Tumor specimens from nine meningiomas were grown as tissue explants. The supernatants from the explants were tested for the presence of the aforementioned cytokines via the enzyme-linked immunosorbent assay method. RESULTS: IL-6, which is thought to stimulate acute protein phase synthesis, neovascularization, and cell proliferation, was found in all of the samples in greater concentrations than the other cytokines tested. IL-1beta, another stimulatory cytokine thought to be involved in acute protein phase synthesis and cell proliferation, was also found in 100% of the samples tested, in concentrations significantly lower than those of IL-6. As expected, the presence of IL-2 and IL-4 was not detectable in any of the samples. CONCLUSION: This study is the first to clearly determine the relative concentrations of IL-1beta and IL-6, using enzyme-linked immunosorbent assay quantification. These findings are an important precursor to future studies using antibodies to IL-1beta and IL-6 and antibodies to IL-6 receptors to modulate neoplastic growth both in vitro and in vivo. (Neurosurgery 39:823829, 1996) Key words: Cytokine, IL-1beta, IL-6, Meningioma ---------------------------------------------------------------------------- Neurosurgery at the Montreal Neurological Institute and McGill University Hospitals William Feindel, M.D., C.M., D.Phil. The Montreal Neurological Institute, and the Division of Neurosurgery, Department of Neurology and Neurosurgery, McGill University, Montreal, Canada FOR THE PAST 60 years, the Montreal Neurological Institute and Hospital and three associated McGill University teaching hospitals have provided a broad course of instruction in neurosurgery and the related neurosciences. This integrated program offers a wealth of experience in adult and pediatric neurosurgery, based on a total of 140 beds, covering a full range of general and subspecialty neurosurgery. The institute, recognized for many years as a world center for epilepsy surgery, has traditional strengths in the treatment of brain tumors and cerebrovascular and spinal disorders; it has been at the cutting edge of brain imaging in all modalities applied to neurosurgical diagnosis and cerebral localization, including three-dimensional monitoring in the operating room. New approaches to stereotactic procedures have been developed in conjunction with imaging technology, including functional neurosurgery and the versatile McGill double rotation method for radiosurgery with a linear accelerator. Experience in managing trauma, pediatric cases, and general neurosurgical problems is gained at the Montreal General Hospital, the Montreal Children's Hospital, and the Jewish General Hospital. Well-established research units, including burgeoning groups in neurogenetics, molecular neurobiology, and neural regeneration, provide a wide variety of academic opportunities to provide trainees with a sound basis for coping with the rapidly advancing field of neurosurgery. (Neurosurgery 39:830839, 1996) Key words: Archibald, Edward; Cone, William; Jewish General Hospital; McGill University; Montreal Children's Hospital; Montreal General Hospital; Montreal Neurological Institute; Neurosurgical Education; Osler, William; Penfield, Wilder; Royal Victoria Hospital ---------------------------------------------------------------------------- Contralateral Cerebellar Hemorrhagic Infarction after Pterional Craniotomy: Report of Five Cases and Review of the Literature Varnavas Papanastassiou, M.D., Richard Kerr, M.S., Christopher Adams, M.Chir. Department of Neurological Surgery, The Radcliffe Infirmary, Oxford, England OBJECTIVE AND IMPORTANCE: Five cases of cerebellar hemorrhagic infarction complicating pterional craniotomy are presented. Recognition of this rare complication may be delayed, with catastrophic consequences, because clinicians are unaware of the possibility. We suggest that the mechanism of this complication is dislocation of the dependent part of the cerebellum and venous obstruction causing hemorrhagic infarction. CLINICAL PRESENTATION: Five patients undergoing pterional craniotomies for benign conditions (four unruptured aneurysms and one meningioma) developed hemorrhagic infarction of the contralateral cerebellum in the postoperative period. This resulted in obstructive hydrocephalus and brain stem compression. A review of the literature revealed only one previous report of a similar complication in patients with gross coagulopathy. This was not a problem in our patients. INTERVENTION: The time of onset of symptoms varied from immediately postoperative to 24 hours later. Once the diagnosis was made, the hydrocephalus was drained and the posterior fossa was decompressed. CONCLUSION: The outcome depended on two variables: 1) the rate of development of hemorrhagic infarction and the associated complications and 2) the amount of time that elapsed before remedial action was taken. Two patients with the first signs of deterioration in the immediate postoperative period had the worst outcome; one died and the other remained severely disabled. In two patients with good neurological recovery, problems were identified and corrected within 4 hours of the first sign of deterioration. Rapid overdrainage of cerebrospinal fluid during supratentorial surgery should be avoided, and the fluid volume should be replaced before closure. Postoperative evaluation of patients whose conditions deteriorate after supratentorial craniotomy should include adequate imaging studies of the posterior fossa. (Neurosurgery 39:841852, 1996) Key words: Cerebellum, Complication, Hemorrhagic infarction, Supratentorial craniotomy ---------------------------------------------------------------------------- Direct Carotid Cavernous Fistula after Trigeminal Balloon Microcompression Gangliolysis: Case Report Todd A. Kuether, M.D., Oisin R. O'Neill, M.D., Gary M. Nesbit, M.D., Stanley L. Barnwell, M.D., Ph.D. Division of Neurosurgery and the Dotter Interventional Institute, Oregon Health Science University, Portland, Oregon OBJECTIVE AND IMPORTANCE: Percutaneous gangliolysis procedures may rarely be associated with vascular complications. There are three reported cases of carotid cavernous fistulas occurring after percutaneous retrogasserian procedures. We present one case of acute symptomatic direct carotid-cavernous fistula after percutaneous balloon microcompressive trigeminal gangliolysis. This is the only reported case of this complication associated with microcompression gangliolysis. CLINICAL PRESENTATION: A 78-year-old woman was referred to our institution with a history of abrupt onset of left-sided bruit, proptosis, chemosis, and diplopia after a percutaneous retrogasserian microcompression. INTERVENTION: Cerebral angiography revealed a large left direct carotid cavernous fistula. Attempts at balloon embolization were unsuccessful, and the lesion was ultimately cured by transarterial and transvenous coil embolization. CONCLUSION: Follow-up examination revealed no evidence of bruit or neurological deficit. This report highlights a unique complication of balloon gangliolysis and describes coil embolization of the fistula as the mode of treatment. (Neurosurgery 39:853856, 1996) Key words: Carotid artery, Carotid-cavernous fistula, Therapeutic embolization, Trigeminal neuralgia ---------------------------------------------------------------------------- Symptomatic Hypertrophic Pacchionian Granulation Mimicking Bone Tumor: Case Report Toshihiko Kuroiwa, M.D., Yoshinaga Kajimoto, M.D., Tomio Ohta, M.D., Akira Tsutsumi, M.D. Department of Neurosurgery and Central Laboratory, Osaka Medical College, Osaka, Japan OBJECTIVE AND IMPORTANCE: Osteolytic lesions can be seen in various diseases, and they also resemble the markings normally found on the cranium. We present a rare case of symptomatic hypertrophic pacchionian granulation mimicking bone tumor in the calvaria. CLINICAL PRESENTATION: A 46-year-old woman suffered from a small hump accompanied by pain in the right frontoparietal region. A plain radiograph revealed two punched-out lesions. Precontrast-enhanced computed tomographic scans demonstrated hypodense masses, with partial defect of the outer table of the cranium. Magnetic resonance imaging demonstrated hypointense masses in the T1-weighted image and hyperintense masses in the T2-weighted image, with capsule-like contrast enhancement by gadolinium diethylenetriamine penta-acetic acid. INTERVENTION: The masses were totally resected with attached bone and dura. One of them had destroyed the outer table of the cranium. The affected portions of the masses lacked the dura and partially adhered to the brain surface. Histologically, hypertrophic pacchionian granulation was diagnosed. CONCLUSION: The patient has had no recurrence for 2 years. This case suggests the need to include hypertrophic pacchionian granulation in the differential diagnosis of punched-out lesions. (Neurosurgery 39:860862, 1996) Key words: Bone tumor, Meningioma, Pacchionian granulation, Punched-out lesion ---------------------------------------------------------------------------- Cervical-to-Petrous Internal Carotid Artery Saphenous Vein in Situ Bypass for the Treatment of a High Cervical Dissecting Aneurysm: Technical Case Report Emmanuel Candon, M.D., Charles Marty-Ane, M.D., Pierre Pieuchot, M.D., Philippe Frerebeau, M.D. Services de Neurochirurgie (EC, PF), Chirurgie Vasculaire (CM-A), and Neuroradiologie (PP), CHU Montpellier, Montpellier, France OBJECTIVE AND IMPORTANCE: We describe a novel cervical-to-petrous internal carotid artery (ICA) saphenous vein in situ bypass for the treatment of a high cervical dissecting aneurysm. The cervical ICA has no major collateral branches and can be used as a tunnel for the vein graft. CLINICAL PRESENTATION: A 25-year-old man was involved in a car accident. A cerebral angiogram revealed a right ICA dissection with aneurysm formation at the C1C2 level. The patient recovered fully and was anticoagulated. Six months after the initial angiogram, a second angiogram disclosed ICA stenosis (80%) and persistence of the traumatic dissecting aneurysm. Definitive surgical bypass was considered the most appropriate course of action. TECHNIQUE: The horizontal portion of the petrous ICA was exposed by an extradural subtemporal approach. The cervical arteries were exposed by a separate cervical incision. After dividing the petrous ICA and the cervical ICA, the cervical ICA was dilated using a Fogarty balloon embolectomy catheter. A saphenous vein graft was inserted inside the lumen of the cervical ICA and was anastomosed to the ICA end-to-end both proximally and distally (cervical-to-petrous ICA in situ bypass). The graft was patent on the follow-up angiogram. CONCLUSION: We describe a new technique that could be considered an alternative to the classical extra-anatomic cervical-to-petrous ICA bypass procedures. (Neurosurgery 39:863866, 1996) Key words: Autologous vein graft, Extracranial-intracranial bypass, Internal carotid artery, Telescopic principle ---------------------------------------------------------------------------- Surgical Needle Design: Torsion Resistance Edward C. Benzel, M.D., Paul J. Parisi, B.S. University of New Mexico, School of Medicine, Division of Neurosurgery (ECB), Albuquerque, New Mexico, and Ethicon, Inc. (PJP), Somerville, New Jersey OBJECTIVE: The interface between a surgical needle and forceps affects needle-forceps stability. Stability has become more important with the introduction of blunt-point surgical needles. The stability at the needle-forceps interface can be assessed by quantitating resistance to both rotation and twisting. Two commonly used surgical needles are the MO and CT needles, which are particularly useful for soft tissue closure for which significant strength of closure is required. Their comparison is thus of importance to surgeons. The design of the MO needle (greater flat section width than the CT needle) should allow for a greater resistance to rotation at the needle-forceps junction. This theoretically makes the MO needle a better choice when blunt-point needles (which require a greater force to penetrate tissue) are used. The objective of this study is to document and quantitate the differences, if any, between the CT and MO needles with regard to rotation and twisting at the needle-forceps junction. METHODS: To compare the efficacy of the CT and MO needles with regard to needle-forceps stability, the resistance of the needles to rotation and twisting was assessed using a Hios HP-10 digital torque meter. RESULTS: The resistance to twisting of the CT and MO needles was not significantly different. However, the MO needle is 25% more resistant to rotation than the CT needle. This differed by 10% from the expected difference. CONCLUSION: The resistance to twisting is not significantly affected by needle geometry, whereas the resistance to rotation is significantly affected. The difference between expected and observed differences in rotation is explained by study design. (Neurosurgery 39:867870, 1996) Key words: Bending, Needle forceps, Rotation, Surgical needle, Torque, Twisting ---------------------------------------------------------------------------- © 1996 Williams & Wilkins