Mandibular reconstruction with a prefabricated vascularized bone graft using recombinant human osteogenic protein-1: an experimental study in miniature pigs. Part I: Prefabrication.

Osteogenic protein-1 (rhOP-1), also called bone morphogenetic protein-7 (BMP-7), is osteoinductive. It may be possible to reconstruct a mandible by local application of rhOP-1. However, in tumour patients this can be impossible due to scars or preceding radiotherapy. Usually vascularized bone grafts are indicated. The aim of this study was to prefabricate a vascularized bone graft in the latissimus dorsi muscle for microsurgical transplantation. In nine minipigs 600 microgram rhOP-1 were used with 8 ml xenogenic bone mineral (BioOss, Geistlich, Waldenburg, Germany) as a carrier and inserted into a pouch prepared in the M. latissimus dorsi. After 6, 12, and 24 weeks the grafts were harvested. The results were evaluated using computed tomography, histology, macro- and microangiography. A high yield of newly formed bone was obtained on the osteoconductive scaffold of the xenogenic bone. It was possible to create a vascularized osseous graft in the given shape of the BioOss blocks. In cross-sections, 68% of the scaffold was coated with new bone. The amount of new bone did not differ between the prefabrication times. Bone overgrowth was 2.1% of the graft volume. In conclusion, this study has shown that it can be possible to prefabricate a neomandible within a muscle graft, which then could be transferred for microvascular reconstruction of the mandible. Further research is required before this technique can be refined for clinical use.

Mandibular reconstruction with prefabricated vascularized bone grafts using recombinant human osteogenic protein-1: an experimental study in miniature pigs. Part II: transplantation.

Osteogenic Protein-1 (rhOP-1), also called bone morphogenetic protein-7 (BMP-7), is osteoinductive. The aim of this study was to present a new surgical technique: the prefabrication of a vascularized bone graft using rhOP-1 and its microsurgical transplantation. During 6 weeks, osteomuscular grafts were prefabricated in the latissimus dorsi muscle of five adult minipigs. Six hundred micrograms rhOP-1 on a carrier of xenogenic bone mineral in block form were used. The grafts were transplanted into defects of the mandibular angles performing a microsurgical anastomosis and using miniplates for fixation. Identical defects of the contralateral side were treated by direct application of 600 microg rhOP-1 and xenogenic bone mineral. A polychrome sequential labelling was applied. After transplantation the bone stayed viable, demonstrated by continuous apposition of fluorochromes (non-decalcified histologic sections) and bone scintigraphy. The reconstructive result was significantly superior in the prefabrication technique, assessed by histology and computerized tomography (CT). In conclusion, the method has a potential to become a clinical alternative for conventional vascularized bone grafts.

Gait analysis in idiopathic normal pressure hydrocephalus--which parameters respond to the CSF tap test?

OBJECTIVES: Normal pressure hydrocephalus (NPH) is an often underestimated cause of hypokinetic gait disorders in the elderly. Diagnosing NPH is a complex problem, since many symptoms overlap with other neurological diseases. The purpose of the present study was to characterize the gait pattern in NPH quantitatively. Additionally, we analyzed the improvement of gait parameters following tapping of cerebrospinal fluid (CSF). METHODS: Gait analysis was performed in 10 patients and 12 age-matched healthy controls during overground and treadmill locomotion. RESULTS: Compared to healthy controls, patients with NPH walked significantly slower, with shorter and more variable strides and a somewhat lower cadence. The feet were not lifted to a normal height and the dorsal extension of the forefoot prior to heel-strike was insufficient. Balance-related gait parameters such as step width and the foot rotation angles were significantly increased in NPH, while their variability was lower. Only some gait parameters improved after tapping 30 ml CSF. Gait velocity increased by about 23% due to an increased stride length, while the cadence remained unchanged. Balance-related gait parameters and the foot-to-floor clearance during swing were not affected by the treatment. CONCLUSIONS: In conclusion, we found a triad of decreased stride length, decreased foot-to-floor clearance and a broad-based gait to be the typical features of the gait abnormality in NPH. Only the stride length improved following a diagnostic spinal tap. These results may help to more reliably diagnose the condition of NPH in a routine clinical setting.

Dural invasion of meningiomas adjacent to the tumor margin on Gd-DTPA-enhanced MR images: histopathologic correlation.

In intracranial meningiomas a flat, contrast-enhancing, dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA-enhanced MR images. We wished to evaluate whether there is a correlation between MR images and meningeal invasion of intracranial meningiomas. The study included 54 patients with intracranial meningioma and the meningeal sign. MR studies included T2-weighted and gadolinium-DTPA-enhanced T1-weighted images in axial, coronal, and sagittal planes. Histopathologic examinations were done on the meningiomas adjacent to the dura mater. The meningeal sign on MRI was observed from 2 up to 35 mm from the main tumor mass in 31 (57 %) of the 54 patients. In 20 of these 31 the histopathologic examination showed tumor invasion, while 11 patients had no tumor invasion but tissue proliferation, hypervascularity, and vascular dilatation. Seven of the 23 meningiomas without the meningeal sign had histologically proven infiltration of the adjacent dura. MR imaging is not able to determine definitive whether or not there is dural infiltration of the meningiomas. In conclusion, resection of the tumor with a wide margin is necessary to achieve complete excision of meningioma and to avoid recurrence.

[The assessment of the morphological changes after ventral diskectomy by thin-section computed tomography]. / Beurteilung morphologischer Veränderungen nach ventraler Diskektomie mittels Dünnschicht-Computertomographie.

PURPOSE: We examined the changes of the intervertebral body space, the morphology of bone cement interponates and vertebrae after cervical discectomy and ventral fusion with high resolution CT. MATERIALS AND METHODS: CT scans were performed on 25 patients preoperatively, one week and six months after cervical discectomy and ventral fusion. RESULTS: There was no change in the size of the interponates. During follow-up new ossifications were found in 18 of the patients, two of them with neurological deficits. While directly after surgery the sagittal spinal canal diameter was enlarged, six months later particularly the lateral width was found to be reduced. After surgery soft tissue already narrowed the spinal canal in similar shape as the former prolapse. CONCLUSION: We conclude that postoperative neurologic deficits can only be partially explained by the described structural changes, because similar findings were made in uncomplicated postoperative courses as well as in patients with deficits.

[Vertebral body metastases: characteristic MRI findings in epidural infiltration]. / Wirbelkörpermetastasen: Charakteristische MR-Befunde bei epiduraler Infiltration.

PURPOSE: In case of lumbar vertebral metastasis associated with anterior epidural carcinomatous infiltration, we have observed that infiltrations tend to respect the midline. This study led to the systematic recognition of these phenomena in vertebral metastases. MATERIALS AND METHODS: 11 patients with 17 vertebral metastases and adjacent anterior epidural infiltration were reviewed retrospectively. All cases were studied by MRI. The routinely used imaging technique included spin echo (SE) T1 and T2 weighted sequences in the sagittal plane native and T1-SE without and with Gd-DTPA in the axial planes. The radiological findings of these phenomena and the anatomy were studied. RESULTS: We observed these phenomena to be uni- or bilateral in 88.3% of all cases with intraspinal anterior epidural carcinomatous infiltration, especially in that part of the vertebral body where the basal vertebral venous plexus was located. CONCLUSION: We conclude that vertebral metastases respect the midline. We interpret this fact as being due the anatomy of the vertebral body and especially its stabilization by the posterior longitudinal ligament. These findings may be helpful in the differential diagnosis of vertebral body metastases with epidural infiltration in contrast to intraspinal processes which proceed with the destruction of the vertebral body.

[Digital chest x-rays with a selenium detector: a prospective comparison with a conventional film-screen combination]. / Digitale Röntgenthoraxaufnahmen mit einem Selendetektor: prospektiver Vergleich mit einer konventionellen Film-Folien-Kombination.

PURPOSE: To compare a new digital chest radiography system that uses amorphous selenium as the x-ray detector, with conventional radiography for the detection of pathological alterations of the chest. MATERIAL AND METHODS: Two observers analysed pairs of posteroanterior and lateral chest radiographs of 95 patients. One pair of radiographs was obtained with the digital selenium chest radiography system, and the other with conventional film-screen technique. 9 criteria were rated using a 4 point scale. Technical parameters were standardised. Radiation dose was measured in both techniques and compared. RESULTS: A total of 855 criteria were rated. 740 findings were diagnosed in accordance on both techniques (740/855 = 87%). 115 criteria (115/855 = 13%) showed deviations. The mean radiation dose for the selenium detector was 0.02 cGy and for the conventional system 0.11 cGy. CONCLUSION: The exposure of radiation is lower using a selenium x-ray detector compared to conventional film-screen technique in chest radiography. The digital selenium system performs well in a clinical setting, providing visualisation of pathological findings as good as a standard screen-film system.

[CT of the talus: the importance of 2- and 3-dimensional reconstructions]. / CT des Talus: Bedeutung zwei- und dreidimensionaler Rekonstruktionen.

PURPOSE: To evaluate the clinical value of sagittal 2D- and 3D-reformations of the talus with and without electronic disarticulation compared to axial slices. MATERIAL AND METHODS: 23 patients with suspected traumatic lesions of the talus underwent 26 diagnostic CT examinations. Axial slices, sagittal reformations, and 3D-reformations without and with electronic disarticulation were performed. The sagittal 2D- and both types of 3D-reformations were compared to the axial slices with regard to their diagnostic information. RESULTS: Axial slices showed involvement of articular facets in 25 cases. Sagittal and 3D-reformations after electronic disarticulation depicted 23 fractures (23/25), 3D-reformations without electronic disarticulation showed none (0/23). Subluxation of the talocalcaneal joint was only visualised on axial slices three times. One complete luxation of this joint was shown on axial slices, sagittal and 3D-reformations without disarticulation. It was not visualised on 3D-reformations after disarticulation. CONCLUSION: The diagnosis must be made based on the axial slices, supported by sagittal reconstructions. 3D-reformations after electronic disarticulation provide a graphic, detailed and readily recognised image of the anatomy of transchondral fractures, and are very helpful in preoperative planning.

[The plain-film radiological changes in the cervical spine following a ventral fusion operation with bone cement]. / Nativradiologische Anderungen der Halswirbelsäule im Verlauf nach ventraler Fusionsoperation mit Knochenzement.

PURPOSE: The usual treatment in cervical nerve root compression syndrome is the ventral fusion with bone cement. We examined the influence of this interponate on the postoperative changes of the cervical spine. MATERIALS AND METHODS: 33 patients were followed-up postoperatively over 6 months, who were treated with 39 ventral fusions because of cervical myelopathy. The lateral view of the cervical spine was used to measure the size of the bone cement interponate, the height of the intervertebral body space and the angle of both vertebral bodies. RESULTS: There was no change on the size of the interponate. Postoperatively there was a slight enlargement of the intervertebral body space. During further follow-up examinations there was a decrease to the preoperative size because of the destruction of the endplates. Similar to this observation, there was a change of the angle in the operated segment. First there was a decrease of the angle, later an increase. 6 months postoperatively the preoperatively status was re-attained. Clinical examination of the patients revealed new neurologic deficits in 10% of the cases. CONCLUSION: We conclude that the postoperative deficits can be only partially explained because the structural changes occur with both the uncomplicated postoperative courses and in patients with postoperative deficits.

[Dura thickening adjacent to intracranial, para-dural space-occupying lesions in MRI. Histologic correlation]. / Duraverdickung am Rand intrakranieller, duranaher Raumforderungen in der MRT. Histologische Korrelation.

PURPOSE: With intracranial tumors a flat, contrast-enhancing, probably dural structure adjacent to the tumor can occasionally be observed on gadolinium-DTPA enhanced MR images. Thers we have attempted to evaluate a tumor infiltration of these enhancement on MRI. MATERIAL AND METHODS: This study included 50 patients, 19 patients had a dural thickening at the tumor base (13 meningiomas and 6 metastases), while 31 patient did not (12 meningiomas and 19 metastases). Studies included plane T2-weighted spin echo (SE) images as well as T1-weighted axial, coronal, or sagittal plains with and without contrast agent. Histopathological examinations, were done on the tumor base adjacent to the dura mater. RESULTS: 7 of 12 meningiomas showed a meningeal thickening on MRI with histopathologically proven tumor infiltration as did also 5 of 6 metastases. But 3 of 12 meningiomas and 15 of 19 metastases without dural thickening at the tumor base also showed tumor invasion into the dura mater. CONCLUSION: MR imaging is still not able to determine whether or not there is a dural infiltration of the tumors base because there was no correlation between MR images and histopathologic results. In conclusion, metastases adjacent to the dura infiltrate the dura mater in a higher percentage than meningiomas.

[Therapy of venous stenosis using wall stents]. / Therapie venöser Stenosen mit Wallstents.

OBJECTIVE: To evaluate the patency of Wallstents implanted for the treatment of venous stenoses in patients with benign or malignant disease. PATIENTS AND METHODS: 22 Wallstents (20 central venous; two peripheral) were implanted during a period of two years in 12 patients (nine men, three women; mean age 57.8 [26-76] years) with malignant venous stenoses (n = 9) or stenosed dialysis shunts (n = 3). Stent diameter ranged from 8-16 mm, length from 32-91 mm. Introduction of the stents were by percutaneous transfemoral catheterisation, in six patients with simultaneous wire placement from a cubital to the femoral vein. The superior vena cava was the involved vessel in six patients (in two each also the subclavian or brachiocephalic veins), in three only the subclavian vein, twice only the inferior vena cava and once the cephalic vein. RESULTS: The patency of the stents was checked after 4.7 +/- 3.6 (1-14) months, in seven patients clinically, by digital subtraction phlebography in three, by computed tomography in two. In nine patients there was no evidence of obstruction to flow or flow was normal. Stent occlusion had occurred in three patients, 4, 9 and 14 months after placement. There were no complications. Five patients died after a mean period of 4.8 +/- 3.6 (1-6.5) months from the underlying disease, without symptoms of obstruction to flow. CONCLUSION: Stent placement should be considered early, as it is a well-tolerated and effective palliative procedure for central venous stenoses associated with malignant disease or stenosis of dialysis shunts.

[The meningeal sign: a new appraisal]. / Das Meningeale Zeichen: eine Neubewertung.

PURPOSE: To evaluate the occurrence of the meningeal sign in meningiomas and metastases. MATERIAL AND METHODS: We studied 20 patients with meningiomas and 17 patients with cerebral metastases adjacent to the dura. MRI studies (Siemens, Magnetom 1,5) included axial T1-weighted and T2-weighted unenhanced as well as gadolinium-DTPA enhanced T1-weighted (axial, coronal, sagittal) SE imaging. In all patients the tumours were resected with the attached dura mater. Histopathological examinations were done, which corresponded to the area of marked enhancement by gadolinium-DTPA. There was no correlation between the occurrence of the meningeal sign and the histopathological examinations. RESULTS: In 20 patients with meningiomas adjacent to the dura we found the meningeal sign in 11 cases. Histologically we observed an increase of collagen fibres and fibrocytes. In 5 of 17 cases with superficial cerebral metastases the meningeal sign was seen, histologically as dura infiltrations and microbleedings. CONCLUSION: The meningeal sign is not specific for meningiomas and can be observed in a wide variety of pathological entities.

[Spiral CT angiography after the application of an iliac artery stent]. / Spiral-CT-Angiographie nach arterieller iliakaler Stentapplikation.

PURPOSE: To evaluate the diagnostic and clinical value of CT-A performing MIP- and SSD-reformations after intraarterial iliac stent application. METHODS: In a prospective study 32 patients underwent CT-A after stent placement in the iliac arteries. The vascular morphology was analyzed regarding neointimal hyperplasia and calcification pattern. The results were compared with those of clinical findings (walking distance), Doppler ultrasound (ankle-brachial index) and DSA. RESULTS: All 47 stents were visible and patent (100%). One misplacement was identified. A good correlation was found between an improved ankle-brachial index and CT-A (88.5%) and extension of the walking distance and CT-A (92.3%). Concerning location, number and grade of stenoses the results between CT-A and DSA matched in 42.1%. An exact mapping of calcified plaques was possible in all cases. CONCLUSIONS: CT-A as MIP is shown to be superior than DSA with regard to calcifications. Complementary to the indirect methods of the ankle-brachial index and walking distance, CT-A is useful for therapy control after vascular stent placement.

[Double spiral CT angiography]. / Doppel-Spiral-CT-Angiographie.

AIM: To evaluate the clinical value of CT angiography using double-spiral CT technique. METHOD: 7 patients with peripheral occlusive disease were examined after stent placement into iliac arteries (5/7) or prior surgery under the clinical suspicion of an occluded vascular graft (2/2). After a delay of 25 sec two spiral CT-scans, each of 32 sec duration, were started. The average interscan delay was between 12-15 sec. The total examination time was about 100 sec and the total range 36 cm using a slice thickness of 3 mm and a table feed of 6 mm/sec. 150 ml of contrast material were injected continuously with 3 ml/sec. RESULTS: All stents were exactly located and diagnosed as patent (6/6) in comparison to intraarterial angiography. Two occluded vascular grafts were diagnosed, confirmed by surgical findings (2/2). Density measurements showed enough of contrast material in the vessels to perform CT-angiography even in the second part of the examination. CONCLUSION: Double-spiral CT angiography is a clinical applicable and helpful method to examine patients with peripheral occlusive disease. It allows to double the examination range without losing the advantages of small slice thickness.

Pancreatic contrast enhancement with Mn-bis pyridoxal ethylene diamine diacetic acid and the influence of a hormonal stimulation of the pancreas in pigs.

RATIONALE AND OBJECTIVES: Pancreatic and hepatic contrast enhancement after different modes of administration of Mn-bis pyridoxal ethylene diamine diacetic acid (Mn-DPDP) and the influence of the hormones secretin and cholecystokinin on the uptake of this new contrast agent were studied by using magnetic resonance (MR) imaging and atomic absorption spectroscopy (AAS) examinations carried out on 13 young domestic pigs. METHODS: Mn-DPDP was administered either as bolus injection or 30-min infusion. The course of contrast enhancement was noted. MR imaging was carried out with or without pancreatic stimulation. The Mn content in pancreatic and hepatic tissue was analyzed by using AAS. RESULTS: Mn-DPDP caused a significant increase (66 +/- 40.1%) in pancreatic signal intensity, an increase in hepatic signal intensity (78 +/- 23.0%), and a significantly higher Mn content on tissue samples of both organs. The results showed a wide individual range. With infusion of Mn-DPDP, pancreatic enhancement was slower, with a peak at 82 +/- 34 min compared with 54 +/- 51 min following bolus injection. The Mn content of both hepatic and pancreatic tissue determined by AAS seemed to be higher after infusion. An incomplete washout of Mn after 24 hr was demonstrated. Hormonal stimulation of the pancreas further increased pancreatic signal intensity but did not influence hepatic contrast enhancement. CONCLUSION: Infusion is the method of choice for administering Mn-DPDP because it causes an increase in hepatic signal intensity but does not change pancreatic enhancement. Although pancreatic hormonal stimulation intensifies enhancement, the increase is not statistically significant, and this practice will not contribute to day-to-day clinical practice.

[Symptomless lung sequestration]. / Die symptomlose Lungensequestration.

Two cases of asymptomatic intralobar pulmonary sequestrations are reported. Chest radiographs showed a solid intrapulmonary mass left posterior at the base. By computed tomography the exact localization and relationship of the sequesters to the surrounding tissue were demonstrated, and a bolus injection of contrast medium revealed the supplying arteries. The arteriography showed a single arterial supply in both cases and their exact course. In the late phase the pulmonary veins were visualized. Finally a suggested diagnostic workup is given.

[Pachymeningeosis(-itis) haemorrhagica chronica interna]. / Pachymeningeosis(-itis) haemorrhagica chronica interna.

A case of chronic internal haemorrhagic pachymeningeosis, a rare disease with uncharacteristic clinical appearance is presented. Derived from pathomorphological and histological findings, the typical CT appearance is described and main differential diagnoses are marked off by their characteristic criteria.

[Quantitative volumetric determinations on MR tomograms in communicating hydrocephalus]. / Quantitative Volumenbestimmungen auf MR-Tomogrammen beim kommunizierenden Hydrozephalus.

For patients with communicating hydrocephalus the implantation of a cardioventricular shunt is mostly an approved therapy. However, indications are frequently problematic and therefore a shunt operation will not be always successful. The proof of periventricular oedemas in addition to clinical signs seems to be a criterion for an indication for implantation and for the selection of a special valve. With the aid of a newly developed computer programme volume estimation of the ventricular system and the periventricular oedemas has been effected for six patients on T2-weighted MR-tomograms (1.5 tesla). Quotients of the different volumes are correlated with cerebrospinal fluid (CSF) pressure obtained during shunt implantation or lumbar measurement. Distinct indications have been found for a correlation between the volume of the periventricular oedemas and the pressure measurements.