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Biomedical subjects

J Harms

Publications and source records attributed to J Harms.

100 records · Page 6Linked to original sources
PubMedDate not supplied

Preoperative embolization of cervical spine tumors.

PURPOSE: To assess the technical success rate, complications, and effect on intraoperative blood loss of preoperative transarterial embolization of cervical spine tumors. METHODS: A retrospective analysis was performed on 38 patients with tumors of the cervical spine; 69 vertebrae were affected. Polyvinyl alcohol particles, coils, gelfoam particles, either alone or in combination, were used for preoperative tumor embolization. After embolization a total of 57 corporectomies with titanium basket implantation were performed. RESULTS: In 36 of 38 patients, complete (n = 27) or partial (n = 9) embolization was achieved. In 23 patients one vertebral artery was completely occluded by coil placement, and in one patient the ipsilateral internal and external carotid arteries were occluded in addition. No neurological complications could be directly related to the embolization, but two postoperative brain stem infarctions occurred. The mean intraoperative blood loss was 2.4 L. CONCLUSION: Transarterial embolization of cervical spine tumors is a safe and effective procedure to facilitate extensive surgery.

Blood Loss, Surgical↗
PubMedDate not supplied

[Anatomic reduction and monosegmental fusion for high-grade developmental spondylolisthesis L5/S1].

INTRODUCTION: Developmental spondylolisthesis leads to lumbosacral kyphosis with retroversion of the sacrum and lumbar hyperlordosis. The overall sagittal profile of the spine is affected. The deformity is progressive during growth. This retrospective study describes a technique for complete reduction with clinical and radiological evaluation. PATIENTS: Thirty-four patients (mean age 16 years 3 months, 10 males, 24 females) with severe developmental spondylolisthesis L5/S1 (Meyerding grades 3 to 5) were operated on between February 1997 and July 2002. METHOD: Reduction was achieved by temporary transpedicular instrumentation of L4. These screws were removed at the end of the operation or 12 weeks later. RESULTS: Mean slippage was corrected from 76 % preoperatively to 10 % postoperatively. Segmental kyphosis L5/S1 improved from + 21 degrees preoperatively to - 7 degrees postoperatively. Sacral inclination was 34 degrees preoperatively, 43 degrees postoperatively, and 47 degrees at latest follow-up. 76 % of the patients were pain free at the latest follow-up. In 4 patients a fusion at L4/5 was performed due to subsequent decompensation. CONCLUSION: The technique described allows for a nearly anatomic reduction with correction of slippage as well as segmental kyphosis. Correction of the local deformity with monosegmental fusion L5/S1 improves dramatically the overall sagittal profile of the spine. Fusion of the primarily healthy segment L4/5 can be avoided.

Adolescent↗
PubMedDate not supplied

[Hemivertebra resection in congenital scoliosis -- early correction in young children].

BACKGROUND: Congenital scoliosis due to hemivertebrae usually progresses during further growth and leads to severe deformities. Early correction in young children is therefore required. PATIENTS: Thirty-six hemivertebrae in 33 children aged 1 to 6 years (average 3 years 5 months) underwent surgical intervention. Mean follow-up was 4.5 years (2 months to 13 years). METHODS: The hemivertebra was resected by a posterior approach. The gap after resection was closed by compression via a transpedicular instrumentation, thus correcting the scoliotic deformity. RESULTS: Mean Cobb angle of the main curve was 45.9 degrees preoperatively, 11.9 degrees postoperatively, and 9.9 degrees at latest follow-up. The compensatory cranial curve improved spontaneously from 18.4 degrees preoperatively to 5.0 degrees postoperatively and 3.7 degrees at latest follow-up. The compensatory caudal curve improved from 21.3 degrees to 6.7 and 5.4 degrees. The angle of kyphosis was 22.8 degrees preoperatively, 8.9 degrees postoperatively, and 6.8 degrees at latest follow-up. There was one infection, 2 pedicle fractures, and 3 implant failures. In 3 patients additional operations were performed due to new developing deformities. CONCLUSION: Correction surgery of congenital scoliosis should be performed early before the development of severe local deformities and secondary structural changes. Posterior resection of the hemivertebrae with transpedicular instrumentation allows for early intervention in very young children. Excellent correction in both the frontal and sagittal planes, and a short segment of fusion allow for normal growth in the unaffected parts of the spine.

Age Factors↗
PubMedDate not supplied

[Preoperative planning and computer assisted surgery in ankylosing spondylitis].

AIM: The following study describes a technique for preoperative planning and computer-assisted correction osteotomy in the treatment of ankylosing spondylitis. The effect on the overall sagittal profile is evaluated. METHOD: Kyphosis was corrected by a posterior closing wedge osteotomy. Angle and localisation of the wedge were exactly planned preoperatively and transferred to a navigation system. The osteotomy was then performed along the premarked lines with image-guided tools. Nine patients aged 40 to 61 years (average 46 years) were operated on. Follow-up time averaged 12 months (1 to 33 months). RESULTS: The planned angle of the wedge osteotomy was an average of 30 degrees (range 24 degrees to 40 degrees ) preoperatively. Postoperatively, the angle averaged 30 degrees as well (range 22 degrees to 41 degrees ). The individual difference between real and planned angle was an average of 2.7 degrees (range 1 degrees to 6 degrees ). Sacral inclination was 23 degrees preoperatively (range-- 6 degrees to 40 degrees ) and was corrected to 40 degrees (range 27 degrees to 49 degrees ). Anterior displacement of the gravity line averaged 112 mm preoperatively (range 47 to 196 mm) and was corrected to 31 mm (range--7 to 135 mm) postoperatively and 38 mm (range-- 21 to 137 mm) at latest follow-up. CONCLUSION: Precise preoperative planning and correction osteotomy exactly according to this planning allow for an excellent correction of the sagittal profile even in severe ankylosing spondylitis. Pelvic tilt and gravity line are normalised, the patient is able to adopt an ergonomic upright position. Navigation facilitates the intraoperative transfer of the preoperative planning.

Adult↗
PubMedDate not supplied

[Transaxial spongiosa-plasty and ventral, temporary atlanto-axial fixation for therapy of dens pseudarthrosis].

PURPOSE: According to literature there is a pseudarthrosis rate of about 1% up to 64% depending on the treatment of the dens fracture (16). Generally the treatment of dens pseudarthrosis consists of the fusion of the joint C1/C2 with or without dens resection. Now, a method is presented whereby, on the one hand the pseudarthrosis is treated, while on the other hand the anatomical structures and physiological function of the joint C1/ C2 are restored. METHOD: The operation consists of a gradual outboring of the base of the dens and the dens axis and filling with autologous cancellous bone. Then follows a lateral, temporary transarticular screw fixation of C1/C2 which guarantees an immobilisation of the filled out dens. A halo-body-jacket is then applied. The removal of the screws of the temporary fixation follows three months post operatively after X-ray control. Then physiotherapy of the cervical spine follows. RESULTS: During 7/93 and 7/97 this operation was carried out on 11 patients. In 9 cases compression screw osteosynthesis was primarily conducted and in 2 cases conservative therapy had preceded. The X-ray follow ups showed on an average of 14 month a stable bony fusion in 10 patients, the clinical follow up examinations on an average of 14 month a normal function. CONCLUSION: The operation presented is indicated in case of dens pseudarthrosis because this accomplished a definite bony fusion without disturbance of the function of the joint C1/C2 in patients not older than 60 years. Disadvantages are to be found in the intraoperatively high X-ray radiation and the 3 month immobilisation.

Adolescent↗
PubMedDate not supplied

A milestone in ribosomal crystallography: the construction of preliminary electron density maps at intermediate resolution.

Preliminary electron density maps of the large and the small ribosomal particles from halophilic and thermophilic sources, phased by the isomorphous replacement method, have been constructed at intermediate resolution. These maps contain features comparable in size with what is expected for the corresponding particles, and their packing arrangements are in accord with the schemes obtained by ab-initio procedures as well as with the motifs observed in thin sections of the crystals by electron microscopy. To phase higher resolution data, procedures are being developed for derivatization by specific labeling of the ribosomal particles at selected locations with rather small and dense clusters. Potential binding sites are being inserted either by site directed mutagenesis or by chemical modifications to facilitate cluster binding on the surface of the halophilic large and the thermophilic small ribosomal particles, which yield the crystals diffracting to highest resolution (2.9 and 7.3 A (1 A = 0.1 nm), respectively). For this purpose, the surface of these ribosomal particles is being characterized and procedures are being developed for quantitative detachment of selected ribosomal proteins and for their incorporation into core particles. The genes of these proteins are being cloned, sequenced, mutated to introduce reactive side groups, mainly cysteines, and overexpressed. In parallel, two in situ small and stable complexes were isolated from the halophilic ribosome. Procedures for their crystal production in large quantities are currently being developed. Models, reconstructed at low resolution from crystalline arrays of ribosomes and their large subunits, are being used for initial low-resolution phasing of the X-ray amplitudes. The interpretation of these models stimulated the design and the crystallization of complexes mimicking defined functional states of a higher quality than those obtained for isolated ribosomes. These models also inspired modelling experiments according to results of functional studies, performed elsewhere, focusing on the progression of nascent proteins.

Base Sequence↗
PubMedDate not supplied

The role of surgery in the treatment of liver metastases for colorectal cancer patients.

BACKGROUND/AIMS: Liver metastases deriving from colorectal cancer can be treated with curative intention in a select number of patients. Controversy does, however, persist pertaining to the impact of adjuvant treatment strategies. The aim of this study is to elucidate upon the various treatment modalities for patients suffering from liver metastases of colorectal primary tumor as well as to provide a rationale for surgical and adjuvant treatment. METHODOLOGY: From November 1987 to September 1998, a total of 449 consecutive patients suffering from liver metastases deriving from a colorectal cancer were documented at our institution in a prolective study. Prognostic factors providing the most beneficial outcome (whether with surgical and/or adjuvant treatment modalities) were analyzed by univariate and multivariate analysis. RESULTS: Whenever possible, curative (R0) surgical resection of colorectal liver metastases provides the most benefit to the patient. Multivariate analysis revealed tumor infiltration of the lymph nodes of the hepatoduodenal ligament and metachronous occurrence of liver metastases as most independent factors related to survival. CONCLUSIONS: Adjuvant post-operative chemotherapy fails to significantly improve survival following resection of liver metastases when compared to the liver resection only group. In patients with unresectable metastases, regional arterial chemotherapy did not improve survival significantly when compared with systemic chemotherapy.

Adult↗