bluuebunny/crossref_metadata_2025 huggingface dataset:
Posterior atlantoaxial facet screw fixation in rheumatoid arthritis
Authors: Eleraky Mohammed Aly , Masferrer Roberto , Sonntag Volker K. H.
Published: June 2009

Object. This retrospective review was conducted to determine the efficacy of transarticular screw fixation in a group of patients who were treated for rheumatoid atlantoaxial instability.

Methods. Thirty-six patients (mean age 63 years) with rheumatoid atlantoaxial instability were treated with posterior atlantoaxial transarticular screw fixation supplemented with an interspinous C1–2 strut graft—cable construct to provide immediate three-point fixation to facilitate bone fusion. Previous attempts at fusions by using bone grafting with wire fixation at other institutions had failed in six of these patients. Six patients underwent transoral odontoid resections for removal of large irreducible pannus as a first-stage procedure, which was followed within 2 to 3 days by the posterior procedure. Postoperatively, 33 patients were placed in hard cervical collars and three required halo vests because of severe osteoporosis. Of eight patients categorized as Ranawat Class II preoperatively, all eight returned to normal after surgery; of eight patients in Ranawat Class III-A preoperatively, four improved to Class II and four remained unchanged. All 20 patients classified as Ranawat Class I preoperatively recovered completely. Pain decreased or resolved in all patients, and there were no complications related to instrumentation. At follow-up review (mean 2 years), 33 patients (92%) had solid bone fusions, and three (8%) had stable fibrous unions.

Conclusions. Posterior atlantoaxial transarticular screw fixation provides a good surgical alternative for the management of patients with rheumatoid atlantoaxial instability. This technique provides immediate three-point rigid fixation of the C1–2 region, thus obviating the need for halo vest immobilization in most cases.
Occipital plagiocephaly: a critical review of the literature
Authors: Rekate Harold L.
Published: June 2009

Object.The literature on occipital plagiocephaly (OP) was critically reviewed to determine the feasibility of establishing treatment recommendations.

Methods.Using standard computerized search techniques, medical literature databases containing peer-review articles dating from 1966 were queried for key words related to OP. The titles of all articles were scanned for relevance, and copies of potentially relevant articles published in English were reviewed. Articles in which treatment was discussed were categorized according to their weight of evidence as Class I (prospective randomized controlled trials), Class II (clinical studies in which data are collected prospectively or retrospective analyses based on clearly reliable data), and Class III (most studies based on retrospectively collected data) to evaluate their contribution to developing a consensus on the treatment of OP.

Of the 4308 articles identified, all but 89 were excluded. Based on the review of these articles, the actual incidence of OP is unknown, and no population-based studies of its incidence or prevalence exist. The reported incidence of lambdoid craniosynostosis ranges from 3 to 20% with differences in diagnostic criteria accounting for the variability. With the possible exception of a lambdoid suture that is replaced by a dense ridge of bone, no other diagnostic criteria have been agreed on. There were no Class I studies and only one Class II study provided comparisons of outcomes in more than one treatment group with outcomes in an untreated group. Recommended treatment options included observation only, mechanical interventions, and a variety of surgical techniques.

Conclusions.Controlled clinical trials are needed before any form of intervention can be recommended for the treatment of OP. If surgery, which is expensive and potentially dangerous, is to continue to play a role in the management of this condition, efforts should be made to determine if patients with untreated OP have suffered from lack of treatment.
Incidence of silent hemorrhage and delayed deterioration after stereotactic brain biopsy
Authors: Kulkarni Abhaya V. , Guha Abhijit , Lozano Andres , Bernstein Mark
Published: June 2009

Object. Many neurosurgeons routinely obtain computerized tomography (CT) scans to rule out hemorrhage in patients after stereotactic procedures. In the present prospective study, the authors investigated the rate of silent hemorrhage and delayed deterioration after stereotactic biopsy sampling and the role of postbiopsy CT scanning.

Methods. A subset of patients (the last 102 of approximately 800 patients) who underwent stereotactic brain biopsies at the Toronto Hospital prospectively underwent routine postoperative CT scanning within hours of the biopsy procedure. Their medical charts and CT scans were then reviewed.

A postoperative CT scan was obtained in 102 patients (aged 17–87 years) who underwent stereotactic biopsy between June 1994 and September 1996. Sixty-one patients (59.8%) exhibited hemorrhages, mostly intracerebral (54.9%), on the immediate postoperative scan. Only six of these patients were clinically suspected to have suffered a hemorrhage based on immediate postoperative neurological deficit; in the remaining 55 (53.9%) of 102 patients, the hemorrhage was clinically silent and unsuspected. Among the clinically silent intracerebral hemorrhages, 22 measured less than 5 mm, 20 between 5 and 10 mm, five between 10 and 30 mm, and four between 30 and 40 mm. Of the 55 patients with clinically silent hemorrhages, only three demonstrated a delayed neurological deficit (one case of seizure and two cases of progressive loss of consciousness) and these all occurred within the first 2 postoperative days. Of the neurologically well patients in whom no hemorrhage was demonstrated on initial postoperative CT scan, none experienced delayed deterioration.

Conclusions. Clinically silent hemorrhage after stereotactic biopsy is very common. However, the authors did not find that knowledge of its existence ultimately affected individual patient management or outcome. The authors, therefore, suggest that the most important role of postoperative CT scanning is to screen for those neurologically well patients with no hemorrhage. These patients could safely be discharged on the same day they underwent biopsy.
Dual-isotope single-photon emission computerized tomography scanning in patients with glioblastoma multiforme: association with patient survival and histopathological characteristics of tumor after high-dose radiotherapy
Authors: Schwartz Richard B. , Holman B. Leonard , Polak Joseph F. , Garada Basem M. , Schwartz Marc S. , Folkerth Rebecca , Carvalho Paulo A. , Loeffler Jay S. , Shrieve Dennis C. , Black Peter McL. , Alexander Eben
Published: June 2009

Object. The study was conducted to determine the association between dual-isotope single-photon emission computerized tomography (SPECT) scanning and histopathological findings of tumor recurrence and survival in patients treated with high-dose radiotherapy for glioblastoma multiforme.

Methods. Studies in which SPECT with 201Tl and 99mTc-hexamethypropyleneamine oxime (HMPAO) were used were performed 1 day before reoperation in 47 patients with glioblastoma multiforme who had previously been treated by surgery and high-dose radiotherapy. Maximum uptake of 201Tl in the lesion was expressed as a ratio to that in the contralateral scalp, and uptake of 99mTc-HMPAO was expressed as a ratio to that in the cerebellar cortex. Patients were stratified into groups based on the maximum radioisotope uptake values in their tumor beds. The significance of differences in patient gender, histological characteristics of tissue at reoperation, and SPECT uptake group with respect to 1-year survival was elucidated by using the chi-square statistic. Comparisons of patient ages and time to tumor recurrence as functions of 1-year survival were made using the t-test.

Survival data at 1 year were presented according to the Kaplan—Meier method, and the significance of potential differences was evaluated using the log-rank method. The effects of different variables (tumor type, time to recurrence, and SPECT grouping) on long-term survival were evaluated using Cox proportional models that controlled for age and gender.

All patients in Group I (201Tl ratio < 2 and 99mTc-HMPAO ratio < 0.5) showed radiation changes in their biopsy specimens: they had an 83.3% 1-year survival rate. Group II patients (201T1 ratio < 2 and 99mTc-HMPAO ratio of ≥ 0.5 or 201Tl ratio between 2 and 3.5 regardless of 99mTc-HMPAO ratio) had predominantly infiltrating tumor (66.6%); they had a 29.2% 1-year survival rate. Almost all of the patients in Group III (201Tl ratio > 3.5 and 99mTc-HMPAO ratio ≥ 0.5) had solid tumor (88.2%) and they had a 6.7% 1-year survival rate. Histological data were associated with 1-year survival (p < 0.01); however, SPECT grouping was more closely associated with 1-year survival (p < 0.001) and was the only variable significantly associated with long-term survival (p < 0.005).

Conclusions. Dual-isotope SPECT data correlate with histopathological findings made at reoperation and with survival in patients with malignant gliomas after surgical and high-dose radiation therapy.
Symptomatic pituitary metastases
Authors: Morita Akio , Meyer Fredric B. , Laws Edward R.
Published: June 2009

Object. The diagnosis and treatment of metastasis to the pituitary gland can be difficult to determine. The goal of this study was to analyze the clinical presentation, treatment, and prognosis of patients who presented with symptomatic pituitary metastasis.

Methods. The cases of 36 patients with symptomatic pituitary metastases were reviewed. The most common primary cancers were breast (33%) and lung (36%). The presenting symptoms included diabetes insipidus, anterior pituitary insufficiency, and retroorbital pain. The overall median length of patient survival following diagnosis of pituitary metastasis was 180 days. In 20 patients (56%), symptoms stemming from pituitary metastasis were the first manifestation of illness. Local control of tumor was associated with significant improvement in survival times (p < 0.05) and amelioration of disabling symptoms including painful ophthalmoplegia and visual field deficits.

Conclusions. Aggressive treatment including both surgical decompression and radiation therapy improves the quality of life in patients suffering from symptomatic pituitary metastasis.
Endovascular treatment of mural-type vein of Galen malformations
Authors: Halbach Van V. , Dowd Christopher F. , Higashida Randall T. , Balousek Peter A. , Ciricillo Samuel F. , Edwards Michael S. B.
Published: June 2009

Object. In this study the authors report on the results of endovascular treatment for mural-type vein of Galen malformations (VGMs) in a group of infants.

Methods. Eight children (six infants and two neonates) who suffered from symptoms caused by a mural-type VGM were treated by means of endovascular therapy. Their age at the time of treatment ranged from 13 days to 19 months (mean 7.6 months). Two neonates and three infants who presented with hydrocephalus and increased head circumference, one of whom was stabilized with a shunt, underwent elective closure of the malformations 3, 4, 6, 6, and 13 months later, respectively. Two patients presented with hemorrhage; one had an intraventricular hemorrhage (IVH) on the 1st day of life and one, a 5-month-old infant, suffered a large parenchymal hemorrhage and an IVH; both patients were immediately cured by means of endovascular techniques. One child presented with a seizure and cortical venous drainage that were treated immediately. Eleven separate treatment sessions were conducted; eight via transarterial femoral access and the remaining three via a transvenous approach. Two patients were treated by using transfemoral transvenous embolization with fibered coils, and one patient required a transtorcular transvenous approach to permit complete closure of the fistula with electrolytically detachable coils. The embolic devices used included silk suture emboli (three patients), electrolytically detachable coils (three patients), and fibered platinum coils (seven patients). In seven patients, complete closure was demonstrated on postembolization arteriographic studies. The eighth patient had stagnant flow in a giant 6-cm varix treated with arterial and venous coils but has not yet undergone follow-up studies. Late follow-up arteriography was performed in four patients at times ranging from 11 to 24 months postprocedure. In one patient, thrombosis of the malformation and shrinkage of the varix were confirmed on follow-up computerized tomography scanning. The remaining three patients have not yet undergone follow-up angiographic examination. Two asymptomatic complications occurred, including separation of the distal catheter, which was removed with a snare device, and a single platinum coil that embolized to the lung, producing no symptoms in 101 months of clinical follow up. The follow-up period ranged from 3 to 105 months, with a mean of 52 months.

Conclusions. Endovascular therapy is the treatment of choice for mural-type VGMs and offers a high rate of cure with low morbidity.
Endovascular embolization of 150 basilar tip aneurysms with Guglielmi detachable coils: results of the Food and Drug Administration multicenter clinical trial
Authors: Eskridge Joseph M. , Song Joon K. , _ _
Published: June 2009

Object.To assess the safety and efficacy of aneurysm embolization performed using Guglielmi detachable coils (GDCs), the authors reviewed the results of a cohort of 150 patients with either ruptured (83 patients) or unruptured (67 patients) basilar tip aneurysms treated with these detachable platinum coil devices in the early part of the United States multicenter GDC clinical trial that led to Food and Drug Administration approval for the device.

Methods.The most common presentation in this cohort of patients was headache (53%). All patients were entered into the trial after neurosurgical assessment excluded them as candidates for surgical clipping of their aneurysms. Greater than 90% coil packing was achieved in 75% of the patients. For those patients in whom follow-up information was available, the mean angiographic and clinical evaluation follow-up time for 61 patients with ruptured aneurysms was 13.7 months (range 0–43 months) and that for the 49 patients with unruptured aneurysms was 9.8 (range 0–40 months). Conservative mortality rates included up to 23% for the ruptured aneurysm group and up to 12% for the unruptured aneurysm group; the rebleeding rate for treated ruptured aneurysms was up to 3.3% and the bleeding rate for unruptured aneurysms up to 4.1%. Permanent deficits due to stroke in patients with ruptured or unruptured aneurysms occurred in up to 5% and 9%, respectively. Vasospasm occurred in 8% of the patients; it was associated with two deaths. Periprocedural mortality was 2.7% (four patients with ruptured aneurysms).

Conclusions.Detachable platinum coil embolization is a promising treatment for ruptured basilar tip aneurysms that are not surgically clippable; in selected patients it offers lower incidences of morbidity and mortality compared with conservative medical management. The role of this procedure in unruptured basilar tip aneurysms is unclear with less supportive results. More long-term follow-up evaluation is necessary and results are expected to improve.
Seasonal pattern of spontaneous cervical artery dissection
Authors: Schievink Wouter I. , Wijdicks Eelco F. M. , Kuiper James D.
Published: June 2009

Object. The etiology of spontaneous cervical artery dissection is poorly understood; however, it may involve genetic and environmental factors. The purpose of this study was to determine whether seasonality of spontaneous cervical artery dissection exists.

Methods. The seasonal pattern of spontaneous cervical artery dissection was analyzed in a group of 200 consecutive patients (104 females and 96 males with a mean age of 44.9 years) who were evaluated using the Rayleigh test during the period from 1970 to 1990. The majority of patients resided in the midwestern section of the United States, where large seasonal fluctuations in climate occur. A circannual periodicity was found in the frequency of spontaneous cervical artery dissections with a peak occurring in October (p < 0.02). The seasonal variation was substantial, with approximately 58% more patients suffering a cervical artery dissection during autumn than during other seasons.

Conclusions. A seasonal pattern of spontaneous cervical artery dissection exists with a peak occurring in October. The cause of the seasonality remains to be explained; however, weather- or infectious disease—related factors may provide etiological leads.
The effect of subarachnoid hemorrhage on mechanisms of vasodilation mediated by cyclic adenosine monophosphate
Authors: Onoue Hisashi , Katusic Zvonimir S.
Published: June 2009

Object.This study was designed to determine whether subarachnoid hemorrhage (SAH) affects the function of the K+channels responsible for relaxation of canine cerebral arteries in response to adenylate cyclase activation.

Methods.The effect of K+channel inhibitors on the arterial relaxation response to forskolin, a direct adenylate cyclase activator, was studied in rings of basilar arteries obtained from normal dogs and dogs in which SAH was induced (double-hemorrhage model). The levels of adenosine 3′,5′-cyclic monophosphate (cAMP) were measured using the radioimmunoassay technique. In rings with the endothelium removed, relaxation induced by forskolin was not affected by SAH. The relaxation response to forskolin was reduced by charybdotoxin (1027 mol/L), a selective Ca++-activated K+channel inhibitor, in normal arteries and arteries subjected to autologous blood injection. This inhibitory effect of charybdotoxin was significantly greater in arteries involved in SAH than in normal vessels. The relaxation response to forskolin was reduced by 4-aminopyridine (10−3mol/L), a delayed rectifier K+channel inhibitor, only in arteries involved in SAH. In contrast, the relaxation response to forskolin was not affected by glyburide (10−5mol/L), an adenosine 5′—triphosphate-sensitive K+channel inhibitor, in both normal and SAH arteries. Forskolin (3 × 10−7mol/L) produced an approximately 10-fold increase in levels of cAMP. The basal values and increased levels of cAMP detected after stimulation with forskolin were no different in normal arteries and those exposed to SAH.

Conclusions.These results demonstrate that formation of cAMP and the relaxation response to adenylate cyclase activation are not affected by SAH. However, in diseased arteries, K+channels assume a more important role in the mediation of relaxation response to forskolin, indicating that SAH may change the mechanisms responsible for vasodilation induced by cAMP.
Familial cervical spondylosis
Authors: Yoo Kevin , Origitano Thomas C.
Published: June 2009

✓ Cervical spondylosis is a disease that is often attributed to aging and considered the result of degenerative changes in the spine. The idea that there is a genetic predisposition to develop diseases of the skeletal elements of the spine has been discussed previously, but has never been proven conclusively. The authors report three cases of severe cervical spondylosis in patients who are first-degree relatives: a mother and her two sons. All three individuals had cervical disc herniations and stenosis at C3–4, C4–5, C5–6, and C6–7, and all three required decompressive procedures. The location and degree of cervical spondylosis were as similar among these three patients as they have been in identical twins reported in other studies. Such familial inheritance of cervical spondylosis has been reported only once. The existence of familial cervical spondylosis is not an unrealistic proposal because other studies have shown that genetics determines the shape of one's spine and that similar spines tend to degenerate in similar ways. Therefore, genetic counseling for a family such as the one reported here may prove to be of great benefit to warn siblings that they are at high risk for cervical spine injury. However rare it might be, familial cervical spondylosis may be a phenomenon that any spine surgeon should suspect in a family with cervical spine abnormalities found in several members.
Neurofibromatosis type 2: growth stimulation of mixed acoustic schwannoma by concurrent adjacent meningioma: possible role of growth factors
Authors: Pallini Roberto , Tancredi Angelo , Casalbore Patrizia , Mercanti Delio , Larocca Luigi M. , Consales Alessandro , Lauretti Liverana , Fernandez Eduardo
Published: June 2009

✓ The authors report the case of a young man suffering from neurofibromatosis type 2 (NF2) who harbored bilateral acoustic schwannomas and a parasellar meningioma. Neuroimaging studies performed during a 4-year follow-up period showed that the bilateral schwannomas had grown very little and at similar rates. However, after the meningioma had infiltrated the tentorium and approached the ipsilateral schwannoma at the incisura, both Schwann cell tumors started to grow rapidly, particularly the one adjacent to the meningioma, of which the percentage of annual growth rate increased by approximately a factor of 102. At the same time, magnetic resonance imaging showed that this tumor also changed its features. During surgery, the acoustic schwannoma was firmly adherent to both meningioma and tentorium. Histological examination revealed meningotheliomatous cells in the schwannoma adjacent to the meningioma. Antiphosphotyrosine immunoblotting of PC12 cells was compatible with the presence of an epidermal growth factor (EGF)—like molecule in the cerebrospinal fluid (CSF) of the patient. This factor was not detected in the CSF of five other NF2 patients, two of whom bore associated bilateral acoustic schwannomas and meningioma in remote locations. It is hypothesized that the meningotheliomatous cells infiltrating the schwannoma triggered an autocrine/paracrine growth—stimulatory mechanism that involved an EGF-like factor.
Long-term follow-up results of laminectomy for cervical myelopathy caused by ossification of the posterior longitudinal ligament
Authors: Kato Yasuji , Iwasaki Motoki , Fuji Takeshi , Yonenobu Kazuo , Ochi Takahiro
Published: June 2009

Object. This retrospective study was performed to assess the long-term results of cervical laminectomy in treating ossification of the posterior longitudinal ligament (OPLL) of the cervical spine.

Methods. The authors reviewed medical records in 44 of 52 patients who underwent cervical laminectomy between 1970 and 1985 (mean follow up 14.1 years). The neurological recovery rate after laminectomy was 44.2% after 1 year and 42.9% after 5 years. The surgical outcome was maintained after 5 years but worsened between 5 and 10 years postsurgery: the recovery rate at the last follow-up review was 32.8%. Using multivariate stepwise analysis, the preoperative factors that affected clinical results were found to be the age at operation, the severity of preexisting myelopathy, and a history of trauma. Late neurological deterioration was observed in 10 (23%) of 44 patients. The earliest deterioration occurred at 1 year and the latest was at 17 years postsurgery (mean 9.5 years). The most frequent cause of deterioration was trauma due to a fall (six patients), followed by ossification of the ligamentum flavum (three patients). Postoperative spread of the OPLL was noted in 70% of the patients, but it was clearly the cause of neurological deterioration in only one of them. After laminectomy, postoperative progression of kyphotic deformity was observed in 47% of patients, but these changes did not cause neurological deterioration.

Conclusions. The authors recommend early surgical decompression for OPLL because the outcome is better for younger patients and for those with a higher score as measured by the Japanese Orthopedic Association's system.
Thoracoscopic microsurgical excision of herniated thoracic discs
Authors: Rosenthal Daniel , Dickman Curtis A.
Published: June 2009

Object. The authors began using thoracoscopy to treat pathological conditions of the spine in 1992. In this study they delineate their clinical experience in which this procedure was used to resect herniated thoracic discs.

Methods. Fifty-five patients underwent thoracoscopy for the resection of herniated thoracic discs. Thirty-six patients presented with myelopathies and 19 with incapacitating thoracic radicular pain. Forty-three patients underwent a single-level, 11 a two-level, and one a three-level discectomy. The mean operative time for thoracoscopic microdiscectomy was 3 hours and 25 minutes (range 80–542 minutes) and the mean blood loss was 327 ml (range 124–1500 ml). Compared with thoracotomy, which was performed in 18 patients, thoracoscopy was associated with a mean of 1 hour less operative time and less than one-half of the blood loss, duration of chest tube drainage, usage of pain medication, and length of hospitalization. Compared with costotransversectomy, which was performed in 15 patients, thoracoscopy permitted more complete resection of calcified and midline thoracic discs because it provided a direct view of the entire anterior surface of the dura. Thoracotomy was associated with a significantly greater incidence of prolonged, disabling intercostal neuralgia compared with the mild transient episodes of intercostal neuralgia associated with thoracoscopy (50% compared with 16%). Thoracotomy also was associated with a significantly higher incidence of postoperative atelectasis and pulmonary dysfunction than thoracoscopy (33% compared with 7%). Clinical and neurological outcomes were excellent (mean follow-up period 15 months). Among the 36 myelopathic patients, 22 completely recovered neurologically; five improved functionally but had some residual myelopathic symptoms; and nine stabilized. Among the 19 patients with isolated thoracic radiculopathies, 15 recovered completely and four improved moderately; no patient had worsened radicular pain.

Conclusions. Thoracoscopic microdiscectomy is a reliable surgical technique that can be performed safely with excellent clinical and neurological results.
Relationships among cerebral perfusion pressure, autoregulation, and transcranial Doppler waveform: a modeling study
Authors: Ursino Mauro , Giulioni Marco , Lodi Carlo Alberto
Published: June 2009

Object. The aim of this study was to analyze how the main values extrapolated from the transcranial Doppler (TCD) waveform (systolic, mean, and diastolic velocity; velocity peak-to-peak amplitude; and pulsatility index [PI]) are affected by changes in intracranial pressure (ICP), systemic arterial pressure (SAP), autoregulation, and intracranial compliance.

Methods. The analysis was performed using a mathematical model of the intracranial dynamics. This model includes a passive middle cerebral artery, the biomechanics of large and small pial arteries subjected to autoregulatory mechanisms, a collapsing venous cerebrovascular bed, the cerebrospinal fluid circulation, and the ICP—volume relationship.

The results indicate that there are approximately three distinct zones characterized by different relationships between cerebral perfusion pressure (CPP) and velocity parameters in patients with preserved autoregulation. In the central autoregulatory zone (CPP > 70 mm Hg) the mean velocity does not change with decreasing CPP, whereas the PI and velocity peak-to-peak amplitude increase moderately. In a second zone (CPP between 40–45 and 70 mm Hg), in which vasodilation of small pial arteries becomes maximal, the mean velocity starts to decrease, whereas the PI and velocity amplitude continue to increase. In the third zone, in which autoregulation is completely exhausted (CPP < 40 mm Hg), arterioles behave passively, mean velocity and velocity amplitude decline abruptly, and the PI exhibits a disproportionate rise. Moreover, this rise is quite independent of whether CPP is reduced by increasing ICP or reducing mean SAP.

In contrast, in patients with defective autoregulation, the mean velocity and velocity amplitude decrease linearly with decreasing CPP, but the PI still increases in a way similar to that observed in patients with preserved autoregulation.

Conclusions. The information contained in the TCD waveform is affected by many factors, including ICP, SAP, autoregulation, and intracranial compliance. Model results indicate that only a comparative analysis of the concomitant changes in ultrasonographic quantities during multimodality monitoring may permit the assessment of several aspects of intracranial dynamics (cerebral blood flow changes, vascular pulsatility, ICP changes, intracranial compliance, CPP, and autoregulation).
Age dependency of resistance to cerebrospinal fluid outflow
Authors: Albeck Michael J. , Skak Claus , Nielsen Per R. , Olsen Karsten S. , Børgesen Svend E. , Gjerris Flemming
Published: June 2009

Object. Resistance to cerebrospinal fluid (CSF) outflow (Rout) is an important parameter in assessing the need for CSF shunt placement in patients with hydrocephalus. The normal lower limit of Rout has been estimated on the basis of the clinical effect of shunt placement in patients with varying values of Rout and in young healthy volunteers. The lack of clinical effect from CSF shunts in some elderly patients, despite elevated Rout, suggests that the normal value of Rout increases with age and may be higher in elderly persons. The aim of the present study was to examine the relationship between Rout and age in patients without known CSF dynamic disturbances.

Methods. Fifty-two patients ranging from 20 to 88 years of age and with no known CSF dynamic disorders were examined. The Rout was measured using a lumbar computerized infusion test. The correlation between Rout and age was analyzed by performing linear regression. The Rout increased significantly with patient age. The Rout in a patient in the eighth decade will be approximately 5 mm Hg/ml/minute higher than in a young patient.

Conclusions. The present study shows a small but critical increase in Rout with increased patient age. A notable residual variation was present and borderline values of Rout should be regarded and used with caution.
Posttraumatic hypothermia in the treatment of axonal damage in an animal model of traumatic axonal injury
Authors: Koizumi Hiroyasu , Povlishock John T.
Published: June 2009

Object. Many investigators have demonstrated the protective effects of hypothermia following traumatic brain injury (TBI) in both animals and humans. Typically, this protection has been evaluated in relation to the preservation of neurons and/or the blunting of behavioral abnormalities. However, little consideration has been given to any potential protection afforded in regard to TBI-induced axonal injury, a feature of human TBI. In this study, the authors evaluated the protective effects of hypothermia on axonal injury after TBI in rats.

Methods. Male Sprague—Dawley rats weighing 380 to 400 g were subjected to experimental TBI induced by an impact-acceleration device. These rats were subjected to hypothermia either before or after injury, with their temporalis muscle and rectal temperatures maintained at 32°C for 1 hour. After this 1-hour period of hypothermia, rewarming to normothermic levels was accomplished over a 90-minute period. Twenty-four hours later, the animals were killed and semiserial sagittal sections of the brain were reacted for visualization of the amyloid precursor protein (APP), a marker of axonal injury. The density of APP-marked damaged axons within the corticospinal tract at the pontomedullary junction was calculated for each animal. In all hypothermic animals, a significant reduction in APP-marked damaged axonal density was found. In animals treated with preinjury, immediate postinjury, and delayed hypothermia, the density of damaged axons was dramatically reduced in comparison with the untreated controls (p < 0.05).

Conclusions. The authors infer from these findings that early as well as delayed posttraumatic hypothermia results in substantial protection in TBI, at least in terms of the injured axons.
Dural cysts in the cervical region
Authors: Hamburger Christoph H. , Büttner Andreas , Weis Serge
Published: June 2009

✓ Dural spinal cysts are exceedingly rare lesions. The authors are aware of only seven cases reported in the literature. This report comprises three patients with dural cysts of the cervical spinal canal who presented with atypical neurological signs and symptoms, including a long history of dysesthesias and atrophic pareses in the proximal upper extremities.

Surgical intervention disclosed two ventrally and one dorsally located cystic lesions of the spinal dura mater. The cystic wall was fenestrated and kept open by a silicone catheter in each case. Histological examination of the excised lesions revealed fibrous connective tissue consistent with dural tissue. No epithelial lining was detected. The lesions were classified as dural cysts. The patients' postoperative courses were uneventful.

Although dural cysts are rare lesions, they must be considered in the differential diagnosis of spinal cystic lesions. Because they are nonaggressive and can be safely drained by microsurgical techniques, patients have a favorable prognosis. Early surgical intervention is mandatory to prevent severe neurological deficits.
Iniencephaly: neuroradiological and surgical features
Authors: Erdinçler Pamir , Kaynar Mehmet Y. , Canbaz Bülent , Koçer Naci , Kuday Cengiz , Çiplak Nejat
Published: June 2009

Iniencephaly is a rare congenital anomaly characterized by spina bifida of the cervical vertebrae, fixed retroflexion of the head on the cervical spine, and occipital bone defect. There are only five reports of surviving patients with iniencephaly. The authors report the case of a newborn who presented with iniencephaly and an encephalocele that were surgically treated in our service. Neurological examination of the patient yielded normal results except for a moderate psychomotor retardation. The neuroradiological and surgical findings of the case suggested that the trigger of the anomaly was the occipital bone defect and rachischisis of the posterior vertebral arches.
Endodermal cysts of the posterior fossa
Authors: Bejjani Ghassan K. , Wright Donald C. , Schessel David , Sekhar Laligam N.
Published: June 2009

✓ The pathogenesis of endodermal cysts of the posterior fossa is still incompletely understood. The authors reviewed three new cases and those reported in the literature to clarify the clinical, pathological, radiological, and surgical characteristics of these lesions. A total of 49 cases were reviewed. Details on demographic profiles, clinical characteristics, histopathological and radiological features, and surgical methods were collected.

These cysts have a predominance in male patients (61%) and can occur at any age (birth–77 years). In patients with posterior fossa endodermal cysts there is a bimodal age distribution and headache is the most frequent complaint. On immunohistopathological examination, endodermal cysts were reactive for epithelial membrane antigen and for keratin immunostains whenever the latter were tested. The cysts were reactive for carcinoembryonic antigen in nine of 11 cases. Endodermal cysts were located anterior to the brainstem in 51% of cases and in the fourth ventricle in 21% of cases. They frequently appeared hypodense on computerized tomography scans, and in five cases, the lesion was missed. The cyst's appearance on magnetic resonance imaging is variable. Resection was complete in 19 cases and partial in 11; marsupialization was achieved in two cases. Three recurrences have been reported.

Total excision with preservation of neurological function should be the goal. Cranial base approaches are helpful for surgical access in selected examples of these lesions.
Orbitozygomatic craniotomy
Authors: Zabramski Joseph M. , Kiriş Talat , Sankhla Suresh K. , Cabiol Josep , Spetzler Robert F.
Published: June 2009

✓ The orbitozygomatic approach provides wide, multidirectional access to the anterior and middle cranial fossae, as well as to the upper third of the posterior fossa and clivus. The authors describe technical details of the surgical approach as it has evolved over 3.5 years of experience in 83 consecutive cases. This modified technique eliminates the need for bone reconstruction of the orbital walls to prevent enophthalmos and minimizes the risk of injury to the frontal branch of the facial nerve. At a follow-up evaluation after a period averaging 14 months, all patients were pleased with the cosmetic results of this approach.
Long-term endocrinological follow-up evaluation in 115 patients who underwent transsphenoidal surgery for acromegaly
Authors: Freda Pamela U. , Wardlaw Sharon L. , Post Kalmon D.
Published: June 2009

Object. The results of surgical therapy for acromegaly were assessed using carefully conducted endocrinological testing in 115 patients who underwent transsphenoidal surgery from 1981 to 1995.

Methods. Ninety-nine of the 115 patients could be contacted for follow-up review; in 57 of the patients an endocrinological assessment was performed by the authors. Biochemical cure was strictly defined as a normalization of the insulin-like growth factor(IGF)—I level (obtained in 100 patients) and/or a basal or glucose-suppressed growth hormone (GH) level of 2 ng/ml or less. The mean length of follow up from transsphenoidal surgery to laboratory testing was 5.4 years with a maximum of 15.7 years. After transsphenoidal surgery alone, 61% of the patients achieved a biochemical remission; the remission rate was 88% for patients with microadenomas and 53% for those with macroadenomas. Tumor size and preoperative GH level tended to correlate negatively with outcome of surgery. Early postoperative GH level tended to correlate with long-term outcome; in cases in which the early postoperative GH level was lower than 3 ng/ml, the chance of long-term remission was 89%. Thirty-two patients received postoperative radiotherapy: in 10 (31%) of these patients the disease is currently in remission after surgery and radiotherapy only and in three others the disease is in remission with the addition of medical therapy. The overall complication rate was 6.9% with no cerebrospinal fluid leaks, meningitis, permanent diabetes insipidus, or new hypopituitarism. The overall recurrence rate was low at 5.4%.

Conclusions. This series shows, based on IFGF—I measurements and strict GH supression criteria to define remission, that transsphenoidal surgery provides an excellent chance for long-term cure in patients with microadenomas. Surgery alone is successful in most patients with noninvasive macroadenomas; however, most patients with invasive macroadenomas will require adjunctive therapy. Recurrences are uncommon when biochemical remission is clearly documented postoperatively.
A clinical comparison of one- and two-screw odontoid fixation
Authors: Jenkins Jeffrey D. , Coric Domagoj , Branch Charles L.
Published: June 2009

Object.The optimal treatment of Type II odontoid fractures is controversial. Various therapies have been used, including nonrigid immobilization, halo orthosis, posterior atlantoaxial arthrodesis, and odontoid screw fixation. Of these, odontoid screw fixation is the only treatment modality that provides immediate stabilization and preserves normal motion at C1–2. It has been suggested in cadaveric biomechanical studies that there is no advantage to using more than one screw for anterior odontoid fixation. The authors compared the clinical safety and efficacy of one- and two-screw anterior odontoid fixation.

Methods.The authors retrospectively reviewed the medical records and radiographs of 42 consecutive patients who had undergone fixation for treatment of odontoid fractures at a single institution between 1989 and 1995.

The group treated with a single screw consisted of 20 patients (11 males and nine females) with an average age of 54 years. The union rate in this group, as determined by postoperative dynamic radiographs, was 81%. The group treated with two screws consisted of 22 patients (13 men and nine women) with an average age of 64 years, whose union rate was 85%.

Conclusions.Anterior odontoid screw fixation is a safe and efficacious treatment for odontoid fractures. In the authors' experience there was no significant difference in the successful union rates achieved with either the one- or two-screw fixation techniques (81% and 85%, respectively; χ2= 0.09, p = 0.76).
Efficacy of pedicle screw fixation in the treatment of spinal instability and failed back surgery: a 5-year review
Authors: Masferrer Roberto , Gomez Carlos H. , Karahalios Dean G. , Sonntag Volker K. H.
Published: June 2009

Object.The goal of this study was to review retrospectively the outcome of 95 patients with various disorders leading to instability of the thoracolumbar and lumbar spine who were treated consecutively via a posterior surgical approach with pedicle screw fixation in which the Texas Scottish Rite Hospital system was used.

Methods.All cases were managed according to the same protocol. Follow-up review averaged 29.6 months. Radiographic evidence of osseous union and the patient's current status were analyzed. Four screws were malpositioned, and there were two dural lacerations of a nerve root and one pedicle fracture. Deep wound infections developed in five patients (5.2%), and three patients had postoperative radicular pain. In one case, the rods disengaged from the screws; in four cases, hardware was removed but there were no broken screws. Neurological deficits improved in 85% of the surviving patients, and no patient was worse neurologically after surgery. The rate of osseous union was 96.8%. Three patients developed pseudarthrosis, one of whom was asymptomatic. Back pain improved in 80 patients. A solid bone fusion, however, was not necessarily associated with decreased back pain.

Conclusions.These results support the use of pedicle screw fixation as an effective and safe procedure for fusion of the thoracolumbar and lumbar spine and support the finding that complications can be minimal when a meticulous surgical technique is used. The proper selection of patients for surgery is probably the most important factor associated with good outcomes.
Defining thresholds for critical ischemia by using near-infrared spectroscopy in the adult brain
Authors: Kirkpatrick Peter J. , Lam Joseph , Al-Rawi Pippa , Smielewski Piotr , Czosnyka Marek
Published: June 2009

Object. Signal changes in adult extracranial tissues may have a profound effect on cerebral near-infrared spectroscopy (NIRS) measurements. During carotid surgery NIRS signals provide the opportunity to determine the relative contributions from the intra- and extracranial vascular territories, allowing for a more accurate quantification. In this study the authors applied multimodal monitoring methods to patients undergoing carotid endarterectomy and explored the hypothesis that NIRS can define thresholds for cerebral ischemia, provided extracranial NIRS signal changes are identified and removed. Relative criteria for intraoperative severe cerebral ischemia (SCI) were applied to 103 patients undergoing carotid endarterectomy.

Methods. One hundred three patients underwent carotid endarterectomy. An intraoperative fall in transcranial Doppler—detected middle cerebral artery flow velocity (%ΔFV) of greater than 60% accompanied by a sustained fall in cortical electrical activity were adopted as criteria for SCI. Ipsilateral frontal NIRS recorded the total difference in concentrations of oxyhemoglobin and deoxyhemoglobin (Total ΔHbdiff). Interrupted time series analysis following clamping of the external carotid artery (ECA) and the internal carotid artery (ICA) allowed the different vascular components of Total ΔHbdiff (ECA ΔHbdiff and ICA ΔHbdiff) to be identified.

Data obtained in 76 patients were deemed suitable. A good correlation between %ΔFV and ICA ΔHbdiff (r = 0.73, p < 0.0001) was evident. Sixteen patients (21%) fulfilled the criteria for SCI. All patients who demonstrated an ICA ΔHbdiff of greater than 6.8 µmol/L showed SCI, and in two patients within this group nondisabling watershed infarction developed, as seen on postoperative computerized tomography scans. No patient with an ICA ΔHbdiff less than 5 µmol/L exhibited SCI or suffered a stroke. Within the resolution of the criteria used an ICA ΔHbdiff threshold of 6.8 µmol/L provided 100% specificity for SCI, whereas an ICA ΔHbdiff less than 5 µmol/L was 100% sensitive for excluding SCI. When Total ΔHbdiff was used without removing the ECA component, no thresholds for SCI were apparent.

Conclusions. Carotid endarterectomy provides a stable environment for exploring NIRS-quantified thresholds for SCI in the adult head.
A novel approach to flow quantification in brain arteriovenous malformations prior to enbucrilate embolization: use of insoluble contrast (Ethiodol droplet) angiography
Authors: Wakhloo Ajay K. , Lieber Baruch B. , Rudin Stephen , Fronckowiak Mary Duffy , Mericle Robert A. , Hopkins L. Nelson
Published: June 2009

Object.Successful therapeutic embolization of arteriovenous malformations (AVMs) of the brain with liquid polymers (glues) requires precise knowledge of highly variable AVM structure and flow velocities and transit times of blood through the AVM nidus. The goal of this study was to improve AVM flow measurement and visualization by the substitution of the insoluble Ethiodol (ethiodized oil) contrast agent for the soluble contrast media normally used in angiographic studies.

Methods.Before enbucrilate embolization of 24 AVM feeding pedicles in 13 patients, standard contrast medium was superselectively injected into each target pedicle, followed by infusion of 20 µl of Ethiodol microdroplets. Transport of contrast material was assessed using high-speed biplane pulsed digital subtraction angiography (DSA) operating at 15 frames per second.

The mean blood flow transit times through AVMs after administration of Ethiodol were found to be approximately half as long as in those measured after injection of soluble contrast materials (0.22 ± 0.10 seconds compared with 0.46 ± 0.19 seconds [mean ± standard deviation]; p < 0.0001). The discrete Ethiodol microdroplets travel with the core flow, more closely approximating the dynamic behavior of enbucrilate, allowing the AVM structure to be traced with high spatial and temporal resolution. There were no inadvertent vessel occlusions or pulmonary complications related to the use of Ethiodol for DSA.

Conclusions.Because of diffusion and convection, forces that decrease concentration, visualization of the contrast front is reduced, often resulting in deceptively long transit times when soluble contrast materials are used. Overestimation may prove dangerous when planning embolizations. The Ethiodol droplet DSA method provides accurate transit time measurements and precise, detailed, and dynamic AVM visualization. Further development of this method will improve the safety and precision of AVM treatments.