Beta—tricalcium phosphate as a substitute for autograft in interbody fusion cages in the canine lumbar spine

2002 ◽  
Vol 97 (3) ◽  
pp. 350-354 ◽  
Author(s):  
Takashiro Ohyama ◽  
Yoshichika Kubo ◽  
Hiroo Iwata ◽  
Waro Taki
Keyword(s):  
Lumbar Spine ◽  
Tricalcium Phosphate ◽  
Interbody Fusion ◽  
Donor Site ◽  
Posterolateral Approach ◽  
Content Type ◽  
Spine Model ◽  
Group A ◽  
Group B ◽  
Fine Print

Object. An interbody fusion cage has been introduced for cervical anterior interbody fusion. Autogenetic bone is packed into the cage to increase the rate of union between adjacent vertebral bodies. Thus, donor site—related complications can still occur. In this study a synthetic ceramic, β—tricalcium phosphate (TCP), was examined as a substitute for autograft bone in a canine lumbar spine model. Methods. In 12 dogs L-1 to L-4 vertebrae were exposed via a posterolateral approach, and discectomy and placement of interbody fusion cages were performed at two intervertebral disc spaces. One cage was filled with autograft (Group A) and the other with TCP (Group B). The lumbar spine was excised at 16 weeks postsurgery, and biomechanical, microradiographic, and histological examinations were performed. Both the microradiographic and histological examinations revealed that fusion occurred in five (41.7%) of 12 operations performed in Group A and in six (50%) of 12 operations performed in Group B. The mean percentage of trabecular bone area in the cages was 54.6% in Group A and 53.8% in Group B. There were no significant intergroup differences in functional unit stiffness. Conclusions. Good histological and biomechanical results were obtained for TCP-filled interbody fusion cages. The results were comparable with those obtained using autograft-filled cages, suggesting that there is no need to harvest iliac bone or to use allo- or xenografts to increase the interlocking strength between the cage and vertebral bone to achieve anterior cervical interbody fusion.

Prevention of postoperative posterior tethering of spinal cord after resection of ependymoma

2003 ◽  
Vol 99 (2) ◽  
pp. 181-187 ◽  
Author(s):  
Takeo Goto ◽  
Kenji Ohata ◽  
Toshihiro Takami ◽  
Misao Nishikawa ◽  
Akimasa Nishio ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Neurological Deterioration ◽  
Fisher Exact Test ◽  
Content Type ◽  
Exact Test ◽  
Spinal Ependymoma ◽  
Group A ◽  
Delayed Neurological Deterioration ◽  
Group B ◽  
Fine Print

Object. The authors evaluated an alternative method to avoid postoperative posterior tethering of the spinal cord following resection of spinal ependymomas. Methods. Twenty-five patients with spinal ependymoma underwent surgery between 1978 and 2002. There were 16 male and nine female patients whose ages at the time of surgery ranged from 14 to 64 years (mean 41.8 years). The follow-up period ranged from 6 to 279 months (mean 112.4 months). In the initial 17 patients (Group A), the procedure to prevent arachnoidal adhesion consisted of the layer-to-layer closure of three meninges and laminoplasty. In the subsequently treated eight patients (Group B), the authors performed an alternative technique that included pial suturing, dural closure with Gore-Tex membrane—assisted patch grafting, and expansive laminoplasty. In Group A, postoperative adhesion was radiologically detected in eight cases (47%), and delayed neurological deterioration secondary to posterior tethering of the cord was found in five cases. In Group B, there was no evidence of adhesive posterior tethering or delayed neurological deterioration. A significant intergroup statistical difference was demonstrated for radiologically documented posterior tethering (p < 0.05, Fisher exact test). Moreover, patients with radiologically demonstrated posterior tethering suffered a significant delayed neurological functional deterioration (p < 0.01, Fisher exact test). Conclusions. This new technique for closure of the surgical wound is effective in preventing of postoperative posterior spinal cord tethering after excision of spinal ependymoma.

A positron emission tomography study of cerebrovascular reserve before and after shunt surgery in patients with idiopathic chronic hydrocephalus

1999 ◽  
Vol 91 (4) ◽  
pp. 605-609 ◽  
Author(s):  
Petra M. Klinge ◽  
Georg Berding ◽  
Thomas Brinker ◽  
Wolfram H. Knapp ◽  
Madjid Samii
Keyword(s):  
Positron Emission Tomography ◽  
Emission Tomography ◽  
Chronic Hydrocephalus ◽  
Content Type ◽  
Cerebrovascular Reserve ◽  
Shunt Placement ◽  
Positron Emission ◽  
Group A ◽  
Group B ◽  
Fine Print

Object. In this study the authors use positron emission tomography (PET) to investigate cerebral blood flow (CBF) and cerebrovascular reserve (CVR) in chronic hydrocephalus.Methods. Ten patients whose mean age was 67 ± 10 years (mean ± standard deviation [SD]) were compared with 10 healthy volunteers who were 25 ± 3 years of age. Global CBF and CVR were determined using 15O—H2O and PET prior to shunt placement and 7 days and 7 months thereafter. The CVR was measured using 1 g acetazolamide. Neurological status was assessed based on a score assigned according to the methods of Stein and Langfitt.Seven months after shunt placement, five patients showed clinical improvement (Group A) and five did not (Group B). The average global CBF before shunt deployment was significantly reduced in comparison with the control group (40 ± 8 compared with 61 ± 7 ml/100 ml/minute; mean ± SD, p < 0.01). In Group A the CBF values were significantly lower than in Group B (36 ± 7 compared with 44 ± 8 ml/100 ml/minute; p < 0.05). The CVR before surgery, however, was not significantly different between groups (Group A = 43 ± 21%, Group B = 37 ± 29%). After shunt placement, there was an increase in the CVR in Group A to 52 ± 37% after 7 days and to 68 ± 47% after 7 months (p < 0.05), whereas in Group B the CVR decreased to 14 ± 18% (p < 0.05) after 7 days and returned to the preoperative level (39 ± 6%) 7 months after shunt placement.Conclusions. The preliminary results indicate that a reduced baseline CBF before surgery does not indicate a poor prognosis. Baseline CBF before shunt placement and preoperative CVR are not predictive of clinical outcome. A decrease in the CVR early after shunt placement, however, is related to poor late clinical outcome, whereas early improvement in the CVR after shunt placement indicates a good prognosis.

Suboccipital and cervical chordomas: the value of aggressive treatment at first presentation of the disease

2002 ◽  
Vol 97 (5) ◽  
pp. 1070-1077 ◽  
Author(s):  
Alexandre Carpentier ◽  
Marc Polivka ◽  
Alexandre Blanquet ◽  
Guillaume Lot ◽  
Bernard George
Keyword(s):  
Clinical Symptoms ◽  
Rank Test ◽  
Aggressive Treatment ◽  
Actuarial Survival ◽  
High Tendency ◽  
Content Type ◽  
Log Rank Test ◽  
Group A ◽  
Group B ◽  
Fine Print

Object. Chordoma is a locally invasive tumor with a high tendency for recurrence for which radical resection is generally recommended. To assess the benefits of aggressive treatment of chordomas, the authors compared results in patients treated aggressively at the first presentation of this disease with results in patients who were similarly treated, but after recurrence. Methods. Among 36 patients with cervical chordomas who were treated at the authors' institution, 22 underwent primary aggressive treatment (Group A) and 14 were treated secondarily after tumor recurrence (Group B). Two cases were excluded from Group A because of unrelated early deaths and three from Group B because of insufficient pre- or postoperative data. Most tumors were located at the suboccipital level and only eight cases at a level below C-2. Radiotherapy and proton therapy were similarly conducted in both groups of patients. The actuarial survival rates were 80 and 65% at 5 and 10 years, respectively, in Group A patients and 50 and 0% at 5 and 10 years, respectively, in Group B patients (p = 0.049, log-rank test). The actuarial recurrence-free rates were 70 and 35% at 5 and 10 years, respectively, in Group A and 0% at 3 years in Group B (p < 0.0001, log-rank test). The numbers of recurrences per year were 0.15 in Group A and 0.62 in Group B (p > 0.05). All other parameters that were analyzed (patient age, delay before diagnosis, clinical symptoms, chondroid type of lesion, and histological features) did not prove to influence prognosis in a statistically significant manner. Conclusions. Aggressive therapy, combining as radical a resection as possible with radiotherapy, seems to improve the prognoses of suboccipital and cervical chordomas when applied at the patient's first presentation with the disease.

Tethered cord syndrome of delayed onset following repair of myelomeningocele

1988 ◽  
Vol 69 (3) ◽  
pp. 393-398 ◽  
Author(s):  
Norihiko Tamaki ◽  
Kunio Shirataki ◽  
Noriaki Kojima ◽  
Yoshiteru Shouse ◽  
Satoshi Matsumoto
Keyword(s):  
Preoperative Evaluation ◽  
Tethered Cord ◽  
Tethered Cord Syndrome ◽  
Clear Understanding ◽  
Mr Images ◽  
Content Type ◽  
Delayed Onset ◽  
Group A ◽  
Group B ◽  
Fine Print

✓ Nine (15%) of 60 patients with repaired myelomeningocele exhibited late deterioration of neurological function with a tethered cord syndrome. Dense adhesions at the lowest laminae and at the site of previous repair were the most common findings at surgery. Postoperatively, 71% of the patients improved. Magnetic resonance (MR) imaging was performed in 29 of the 60 patients. Eight of these 29 patients exhibited a tethered cord syndrome. The MR images in all patients showed a low-lying conus fixed at the site of previous repair, irrespective of the presence or absence of a tethered cord syndrome. The MR images were classified into two groups depending upon the site of adhesions: Group A had potential sites of tethering at the ventral aspect of the last laminae and at the site of previous repair, and Group B showed the adhesion point only at the site of previous repair. Most patients with a tethered cord syndrome were found to be in Group A; conversely, most patients without the syndrome were in Group B. An enlarged low conus was seen in symptomatic patients more commonly than in those without this syndrome. It is concluded that the presence of adhesions specifically at the last laminae as well as a widened low-lying conus may be the cause of tethered cord syndrome in patients with repaired myelomeningoceles. A clear understanding of the tethering process and preoperative evaluation of potential sites of tethering, based on the MR findings, are very important for planning surgery. The release of adhesions at the lowest laminae by laminectomy appeared essential for improvement.

Lymphocytic infiltrates in primary glioblastomas and recidivous gliomas

1978 ◽  
Vol 49 (6) ◽  
pp. 854-861 ◽  
Author(s):  
Lucio Palma ◽  
Nicola Di Lorenzo ◽  
Beniamino Guidetti
Keyword(s):  
Immune Response ◽  
Clinical Course ◽  
Lymphocytic Infiltration ◽  
The Other ◽  
Content Type ◽  
X Ray ◽  
Group A ◽  
Group B ◽  
Lymphocytic Infiltrates ◽  
Fine Print

✓ The correlation existing in several human malignancies between lymphocytic infiltration and prolonged survival prompted this study. Two hundred selected patients who were operated on for glioblastoma were reviewed to investigate the incidence of the lymphocytic infiltration in the histological slides and its possible relevance to a better clinical course. The group that exhibited a definite lymphocytic infiltration (Group A, 11.5%) had a significantly longer preoperative history and postoperative survival (p < 0.01) than the other two groups that presented slight or no infiltration (Group B, 23%, and Group C, 65%, respectively). In addition, biopsies of 28 recidivous gliomas were reviewed to study the fate of this lymphocytic infiltration in relation to time and therapy, such as irradiation and steroids which are known to depress the immune response. The authors found that severe lymphocytic infiltration is a rare immunobiological reaction which significantly improves the prognosis of a malignant brain tumor and seems not to be influenced by time, local x-ray therapy, or steroids.

In vitro biomechanical investigation of the stability and stress-shielding effect of lumbar interbody fusion devices

2000 ◽  
Vol 93 (2) ◽  
pp. 259-265 ◽  
Author(s):  
Masahiro Kanayama ◽  
Bryan W. Cunningham ◽  
Charles J. Haggerty ◽  
Kuniyoshi Abumi ◽  
Kiyoshi Kaneda ◽  
...  
Keyword(s):  
Interbody Fusion ◽  
Stress Shielding ◽  
Shielding Effect ◽  
Lumbar Interbody Fusion ◽  
Content Type ◽  
Different Types ◽  
Spine Model ◽  
Structural Allografts ◽  
Fine Print

Object. Interbody fusion devices are rapidly gaining acceptance as a method of ensuring lumbar interbody arthrodesis. Although different types of devices have been developed, the comparative reconstruction stability remains controversial. It also remains unclear how different stress-shielded environments are created within the devices. Using a calf spine model, this study was designed to compare the construct stiffness afforded by 11 differently designed lumbar interbody fusion devices and to quantify their stress-shielding effects by measuring pressure within the devices. Methods. Sixty-six lumbar specimens obtained from calves were subjected to anterior interbody reconstruction at L4–5 by using one of the following interbody fusion devices: four different threaded fusion cages (BAK device, BAK Proximity, Ray TFC, and Danek TIBFD), five different nonthreaded fusion devices (oval and circular Harms cages, Brantigan PLIF and ALIF cages, and InFix device); two different types of allograft (femoral ring and bone dowel) were used. Construct stiffness was evaluated in axial compression, torsion, flexion, and lateral bending. Prior to testing, a silicon elastomer was injected into the cages and intracage pressures were measured using pressure needle transducers. Conclusions. No statistical differences were observed in construct stiffness among the threaded cages and nonthreaded devices in most of the testing modalities. Threaded fusion cages demonstrated significantly lower intracage pressures compared with nonthreaded cages and structural allografts. Compared with nonthreaded cages and structural allografts, threaded fusion cages afforded equivalent reconstruction stiffness but provided more stress-shielded environment within the devices.

Surgical treatment of intractable epilepsy accompanying cortical dysplasia

2000 ◽  
Vol 93 (5) ◽  
pp. 766-773 ◽  
Author(s):  
Seung-Chyul Hong ◽  
Kwan-Soo Kang ◽  
Dae Won Seo ◽  
Seung Bong Hong ◽  
Munhyang Lee ◽  
...  
Keyword(s):  
Surgical Treatment ◽  
Intractable Epilepsy ◽  
Mr Images ◽  
Seizure Onset ◽  
Content Type ◽  
Group A ◽  
The Mean ◽  
Group B ◽  
Group D ◽  
Fine Print

Object. Surgical treatment of cortical dysplasia (CD) together with intractable seizures is challenging because both visualization and localization of the lesion are difficult, correlation with seizure foci requires comprehensive study, and the surgical outcomes reported thus far are unsatisfactory. The authors report their experience in the surgical treatment of CD classified according to a surgical point of view.Methods. The definition of CD used in this study was a dysplastic lesion visible on magnetic resonance (MR) images or a lesion that, although not visible on MR images, was diagnosed as moderate-to-severe dysplasia by using pathological analysis. During the last 4.5 years, the authors treated 36 patients with intractable epilepsy accompanied by CD. They divided the 36 cases of CD into four characteristic groups: Group A, diffuse bilateral hemispheric dysplasia; Group B, diffuse lobar dysplasia; Group C, focal dysplasia; and Group D, a moderate to severe degree of CD with a normal appearance on MR images. All but one patient in Group C were monitored in the epilepsy monitoring unit by using subdural electrodes for seizure localization and functional mapping.The incidence of CD among a cohort of 291 patients who had undergone epilepsy surgery at the authors' center during the study period was 12.4%. The mean age of the 36 patients was 21.3 years and the mean age at seizure onset was 8.5 years. The mean follow-up period was 26 months. Twenty-six patients (72.2%) belonged to Engel Class I or II (20 and six, respectively). There were five cases in Group A, nine in Group B, nine in Group C, and 13 in Group D. Patients in Groups A and B were significantly younger at seizure onset and had significantly poorer surgical outcomes compared with patients in Groups C and D (p < 0.05). If outcome is compared on the basis of the extent of removal of CD, patients in whom CD was completely removed had significantly better outcomes than those in whom CD was only partially removed (p < 0.001).Conclusions. The authors conclude that intractable epilepsy accompanied by CD can be treated surgically using comprehensive preoperative approaches. Deliberate resective procedures aimed at complete removal of dysplastic tissue ensure excellent seizure control without permanent neurological deficit.

Role of estrogen deficiency in the formation and progression of cerebral aneurysms. Part II: experimental study of the effects of hormone replacement therapy in rats

2005 ◽  
Vol 103 (6) ◽  
pp. 1052-1057 ◽  
Author(s):  
Mohammad A. Jamous ◽  
Shinji Nagahiro ◽  
Keiko T. Kitazato ◽  
Tetsuya Tamura ◽  
Kazuyuki Kuwayama ◽  
...  
Keyword(s):  
Hormone Replacement Therapy ◽  
Replacement Therapy ◽  
Hormone Replacement ◽  
Cerebral Aneurysms ◽  
Induction Procedure ◽  
Content Type ◽  
Group A ◽  
Group B ◽  
Fine Print

Object. The increased incidence of cerebral aneurysms in postmenopausal women appears to be related to low levels of circulating estrogen. Using a rat model of aneurysm induction, the authors found that oophorectomy increased the incidence of experimental cerebral aneurysms (Part I in this issue). In the current study they examined the effects of hormone replacement therapy (HRT) on the formation of cerebral aneurysms in rats. Methods. Forty-five female Sprague—Dawley rats were divided into three equal groups. The animals in Groups A and B were subjected to a cerebral aneurysm induction procedure (renal hypertension and right common carotid artery ligation) followed 1 month later by bilateral oophorectomy. After an additional week the rats in Group A received 17β estradiol continuous-release pellets. The rats in Group C served as controls. Three months after the aneurysm induction procedure, all the rats were killed and vascular corrosion casts of their cerebral arteries were prepared and checked for aneurysmal changes. Using a scanning electron microscope, the authors recorded aneurysmal changes as endothelial changes alone (Stage I), endothelial changes with intimal pad elevation (Stage II), and saccular aneurysm formation (Stage III). Aneurysmal changes (Stages I, II, and III) occurred in one third of rats that had undergone oophorectomy and were receiving HRT (Group A), compared with 87% of the rats that had undergone oophorectomy but did not receive HRT (Group B). Although most of the aneurysmal changes identified in Group A rats were limited to Stage I or II, most changes in Group B animals were identified as saccular dilation (Stage III). Conclusions. The findings demonstrated the significant protective role of estrogen against the formation and progression of cerebral aneurysms. It appears to be related to the beneficial effects of estrogen on the function and growth of endothelial cells, which play a major role in preserving the integrity of the vascular wall.

Clinical and pathological effects of bromocriptine on prolactin-secreting and other pituitary tumors

1984 ◽  
Vol 60 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Daniel L. Barrow ◽  
George T. Tindall ◽  
Kalman Kovacs ◽  
Michael O. Thorner ◽  
Eva Horvath ◽  
...  
Keyword(s):  
Tumor Size ◽  
Pituitary Tumors ◽  
Size Reduction ◽  
Pathological Examination ◽  
Primary Therapy ◽  
Pathological Changes ◽  
Content Type ◽  
Group A ◽  
Group B ◽  
Fine Print

✓ Bromocriptine inhibits prolactin secretion and causes size reduction of prolactin-secreting adenomas. The effect of the drug upon pituitary tumors other than prolactinomas is uncertain. The authors report a prospective series of 12 patients with pituitary macroadenomas in whom bromocriptine was administered for 6 weeks prior to transsphenoidal surgery. Five of the patients had computerized tomographic documentation of significant reductions in tumor size (Group A) and six had no change (Group B) during 3 and 6 weeks of bromocriptine administration. One patient who demonstrated size reduction in his tumor was not assigned to either group as he was treated with high-dose dexamethasone concurrently with the bromocriptine. Pathological examination (light and electron microscopy and immunocytochemistry) indicated that all Group A patients harbored tumors with prolactin granules whereas all Group B tumors lacked such granules. Adenoma cells in the responsive tumors were involuted with reduced cytoplasmic, nuclear, and nucleolar areas. Neither widespread cell necrosis, infarction, nor vascular injury was observed. Two of the five Group A patients discontinued bromocriptine prior to completion of the 6-week protocol and had a rapid return of their tumors to pre-treatment size. Although bromocriptine has been reported to cause shrinkage of nonfunctional tumors, there was no radiological evidence of size reduction or pathological changes in the nonfunctional tumors of this series. Interestingly, serum levels of prolactin were modestly elevated (84 and 113 ng/ml) in two of the six Group B patients, an elevation due to stalk compression rather than secretion by adenoma cells. This finding underscores the fact that failure of bromocriptine to reduce pituitary tumor size in the presence of hyperprolactinema may occur because the tumor is other than a prolactinoma. This is the first moderate-sized group of patients in whom pathological changes in responsive prolactinomas during bromocriptine therapy have been demonstrated. As bromocriptine is not tumoricidal, and thus not curative, there is insufficient evidence to recommend this drug as primary therapy for either prolactin-secreting or nonfunctional macroadenomas, but the drug may have potential as a preoperative adjunct to effect shrinkage of prolactinomas and theoretically, at least, make excision easier and possibly more complete.

Is stagnating flow in former feeding arteries an indication of cerebral hypoperfusion after resection of arteriovenous malformations?

2001 ◽  
Vol 95 (1) ◽  
pp. 36-43 ◽  
Author(s):  
Bernhard Meyer ◽  
Horst Urbach ◽  
Carlo Schaller ◽  
Johannes Schramm
Keyword(s):  
Brain Tissue ◽  
Arteriovenous Malformations ◽  
Cerebral Hypoperfusion ◽  
Clear Trend ◽  
Content Type ◽  
Before And After ◽  
Group A ◽  
Cortical Ischemia ◽  
Group B ◽  
Fine Print

Object. The authors' goal in this study was to challenge the proposed mechanism of the occlusive hyperemia theory, in which it is asserted that stagnating flow in the former feeding arteries of cerebral arteriovenous malformations (AVMs) leads to parenchymal hypoperfusion or ischemia, from which postoperative edema and hemorrhage originate. Methods. Cortical oxygen saturation (SaO2) was measured in 52 patients by using microspectrophotometry in areas adjacent to AVMs before and after resection. The appearance of the former feeding arteries was categorized as normal (Group A); moderately stagnating (Group B); and excessively stagnating (Group C) on postoperative angiographic fast-film series. Patients and SaO2 values were pooled accordingly and compared using analysis of variance and Duncan tests (p < 0.05). Angiographic stagnation times in former feeding arteries were correlated in a linear regression/correlation analysis with SaO2 data (p < 0.05). All values are given as the mean ± standard deviation. The average median postoperative SaO2 in Group C (15 patients) was significantly higher than in Groups B (17 patients) and A (20 patients) (Group C, 75.2 ± 8.5; Group B, 67.5 ± 10.8; Group A, 67.1 ± 12 %SaO2), as was the average postoperative increase in SaO2 (Group C, 25.9 ± 14.9; Group B, 14.6 ± 14; Group A, 11.1 ± 14 %SaO2). Angiographically confirmed stagnation times were also significantly longer in Group C than in Group B (Group C, 5.6 ± 2.5; Group B, 1.3 ± 0.6 seconds). A significant correlation/regression analysis showed a clear trend toward higher postoperative SaO2 levels with increasing stagnation time. Conclusions. Stagnating flow in former feeding arteries does not cause cortical ischemia, but its presence on angiographic studies is usually indicative of hyperperfusion in the surrounding brain tissue after AVM resection. In the context of the pathophysiology of AVMs extrapolations made from angiographically visible shunt flow to blood flow in the surrounding brain tissue must be regarded with caution.

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