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Gaa R, Kumari K, Mayer HM, Yanakieva D, Tsai SP, Joshi S, Guenther R, Doerner A. An integrated mammalian library approach for optimization and enhanced microfluidics-assisted antibody hit discovery. Artif Cells Nanomed Biotechnol 2023; 51:74-82. [PMID: 36762883 DOI: 10.1080/21691401.2023.2173219] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Recent years have seen the development of a variety of mammalian library approaches for display and secretion mode. Advantages include library approaches for engineering, preservation of precious immune repertoires and their repeated interrogation, as well as screening in final therapeutic format and host. Mammalian display approaches for antibody optimization exploit these advantages, necessitating the generation of large libraries but in turn enabling early screening for both manufacturability and target specificity. For suitable libraries, high antibody integration rates and resulting monoclonality need to be balanced - we present a solution for sufficient transmutability and acceptable monoclonality by applying an optimized ratio of coding to non-coding lentivirus. The recent advent of microfluidic-assisted hit discovery represents a perfect match to mammalian libraries in secretion mode, as the lower throughput fits well with the facile generation of libraries comprising a few million functional clones. In the presented work, Chinese Hamster Ovary cells were engineered to both express the target of interest and secrete antibodies in relevant formats, and specific clones were strongly enriched by high throughput screening for autocrine cellular binding. The powerful combination of mammalian secretion libraries and microfluidics-assisted hit discovery could reduce attrition rates and increase the probability to identify the best possible therapeutic antibody hits faster.
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Affiliation(s)
- Ramona Gaa
- Protein Engineering and Antibody Technologies, Merck KGaA, Darmstadt, Germany
| | - Kavita Kumari
- Discovery Biology, Syngene International, Phase-IV, Bangalore, India
| | - Hannah Melina Mayer
- Protein Engineering and Antibody Technologies, Merck KGaA, Darmstadt, Germany
| | - Desislava Yanakieva
- Protein Engineering and Antibody Technologies, Merck KGaA, Darmstadt, Germany
| | - Shang-Pu Tsai
- Protein Engineering and Antibody Technologies, EMD Serono, Billerica, MA, USA
| | - Saurabh Joshi
- Discovery Biology, Syngene International, Phase-IV, Bangalore, India
| | - Ralf Guenther
- Protein Engineering and Antibody Technologies, Merck KGaA, Darmstadt, Germany
| | - Achim Doerner
- Protein Engineering and Antibody Technologies, Merck KGaA, Darmstadt, Germany
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Gaa R, Mayer HM, Noack D, Kumari K, Guenther R, Tsai SP, Ji Q, Doerner A. Mammalian display to secretion switchable libraries for antibody preselection and high throughput functional screening. MAbs 2023; 15:2251190. [PMID: 37646089 PMCID: PMC10469430 DOI: 10.1080/19420862.2023.2251190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/10/2023] [Accepted: 08/20/2023] [Indexed: 09/01/2023] Open
Abstract
Recently, there has been a co-evolution of mammalian libraries and diverse microfluidic approaches for therapeutic antibody hit discovery. Mammalian libraries enable the preservation of full immune repertoires, produce hit candidates in final format and facilitate broad combinatorial bispecific antibody screening, while several available microfluidic methodologies offer opportunities for rapid high-content screens. Here, we report proof-of-concept studies exploring the potential of combining microfluidic technologies with mammalian libraries for antibody discovery. First, antibody secretion, target co-expression and integration of appropriate reporter cell lines enabled the selection of in-trans acting agonistic bispecific antibodies. Second, a functional screen for internalization was established and comparison of autocrine versus co-encapsulation setups highlighted the advantages of an autocrine one cell approach. Third, synchronization of antibody-secreting cells prior to microfluidic screens reduced assay variability. Furthermore, a display to secretion switchable system was developed and applied for pre-enrichment of antibody clones with high manufacturability in conjunction with subsequent screening for functional properties. These case studies demonstrate the system's feasibility and may serve as basis for further development of integrated workflows combining manufacturability sorting and functional screens for the identification of optimal therapeutic antibody candidates.
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Affiliation(s)
- Ramona Gaa
- NBE Technologies, Merck KGaA, Darmstadt, Germany
| | | | | | - Kavita Kumari
- Discovery Biology, Syngene International, Bangalore, India
| | | | | | - Qingyong Ji
- NBE Technologies, EMD Serono, Billerica, MA, USA
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Gaa R, Mayer HM, Noack D, Doerner A. Efficient Microfluidic Downstream Processes for Rapid Antibody Hit Confirmation. Methods Mol Biol 2023; 2681:327-341. [PMID: 37405656 DOI: 10.1007/978-1-0716-3279-6_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2023]
Abstract
Microfluidics has been recently applied to better understand the spatial and temporal progression of the immune response in several species, for tool and biotherapeutic production cell line development and rapid antibody hit discovery. Several technologies have emerged that allow interrogation of large diversities of antibody-secreting cells in defined compartments such as picoliter droplets or nanopens. Mostly primary cells of immunized rodents but also recombinant mammalian libraries are screened for specific binding or directly for the desired function. While post-microfluidic downstream processes appear as standard steps, they represent considerable and interdependent challenges that can lead to high attrition rates even if original selections had been successful. In addition to next-generation sequencing recently described in depth elsewhere, this report aims at in detail explanations of exemplary droplet-based sorting followed by single-cell antibody gene PCR recovery and reproduction or single-cell sub-cultivation for crude supernatant confirmatory studies.
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Affiliation(s)
- Ramona Gaa
- Protein Engineering and Antibody Technologies, Merck Healthcare KGaA, Darmstadt, Germany
| | - Hannah Melina Mayer
- Protein Engineering and Antibody Technologies, Merck Healthcare KGaA, Darmstadt, Germany
| | - Daniela Noack
- Protein Engineering and Antibody Technologies, Merck Healthcare KGaA, Darmstadt, Germany
| | - Achim Doerner
- Protein Engineering and Antibody Technologies, Merck Healthcare KGaA, Darmstadt, Germany.
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Heider FC, Mayer HM. [Surgical treatment of lumbar disc herniation]. Oper Orthop Traumatol 2016; 29:59-85. [PMID: 27689222 DOI: 10.1007/s00064-016-0467-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/26/2016] [Accepted: 03/18/2016] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Herniated disc tissue removal to decompress the spinal nerve/cauda equina. Minimization of iatrogenic trauma and associated injuries. INDICATIONS Conservative treatment did not sufficiently improve clinical symptoms. This is true for progressive or persisting neurological deficits, as well as for persisting pain which alters the quality of the patient`s life. Results of surgery are strongly dependent on the preoperative duration of symptoms. Paramount is the "timing" of surgery: poorer surgical results associated with increasing preoperative duration of symptoms. CONTRAINDICATIONS Conservative treatment modalities have not been exhausted. SURGICAL TECHNIQUES There are 2 technologies (endoscopic/microsurgical) and 5 different approach strategies (endoscopic: interlaminar, transforaminal; microsurgical: interlaminar, translaminar, extraforaminal), whereby the choice is determined by morphology and location of the herniated disc. All techniques are minimally invasive and lead to comparable clinical results. POSTOPERATIVE MANAGEMENT For all techniques, patients are mobilized early. Light sports activities allowed after 2 weeks and return to work after about 4 weeks. RESULTS Good clinical outcomes in meta-analyses/large case series are between 80-95 %.
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Affiliation(s)
- F C Heider
- Schön Klinik München Harlaching, Wirbelsäulenzentrum, Akademisches Lehrkrankenhaus und Institut für Wirbelsäulenforschung der Paracelsus Medizinischen Privatuniversität Salzburg (PMU), Österreich, Harlachinger Str. 51, 81547, München, Deutschland.
| | - H M Mayer
- Schön Klinik München Harlaching, Wirbelsäulenzentrum, Akademisches Lehrkrankenhaus und Institut für Wirbelsäulenforschung der Paracelsus Medizinischen Privatuniversität Salzburg (PMU), Österreich, Harlachinger Str. 51, 81547, München, Deutschland
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Heider FC, Mayer HM, Siepe CJ. Lumbar disc replacement: update. J Neurosurg Sci 2015; 59:169-180. [PMID: 25649068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Over the last decades, fusion of lumbar spinal motion segments has represented the mainstay of treatment of lumbar degenerative conditions which failed to respond adequately to conservative therapy. Increasing demands and expectations from patients as well as the necessity to avoid fusion related negative side effects such as adjacent level disc degeneration, considerable complication and reoperation rates, cranial facet joint violations, pseudarthrosis and others led to the development of motion preserving technologies such as total lumbar disc replacement (TDR). The first and rudimentary attempts to preserve motion of lumbar motion segments can be dated back to the early 1950s. Over the past two to three decades, a variety of new implants with different motion characteristics have been developed and introduced into the market. Despite of the extensive knowledge which has been gained in this field of research, insurers in the United States have refused to reimburse surgeons due to fear of late complications and reoperations as well as unknown secondary costs, which led to a global decline in the numbers of TDR procedures. The current literature review intends to provide a concise summary of the adequate indications for TDR as well as outcome determining factors and delineate the role of TDR in the currently available armamentarium for the treatment of low back pain (LBP) resulting from degenerative disc disease (DDD) without instabilities or deformities.
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Affiliation(s)
- F C Heider
- Schön Klinik München Harlaking, Munich, Germany -
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Mayer HM, Heider F. [Selective, microsurgical cross-over decompression of multisegmental degenerative lumbar spinal stenoses: the "Slalom" technique]. Oper Orthop Traumatol 2013; 25:47-62. [PMID: 23400667 DOI: 10.1007/s00064-012-0196-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Selective, bilateral multisegmental microsurgical decompression of lumbar spinal canal stenosis through separate, alternating cross-over approaches. INDICATIONS Two- and multisegmental degenerative central and lateral lumbar spinal stenoses. CONTRAINDICATIONS None (however, if stabilization is necessary, the Slalom technique is not possible). SURGICAL TECHNIQUE Minimally invasive, muscle-sparing and facet-joint-sparing bilateral decompression of the lumbar spinal canal through 2 or more alternating microsurgical cross-over approaches from one side. POSTOPERATIVE MANAGEMENT Early mobilization 4-6 h postoperatively. Soft lumbar brace for 4 weeks (optional). RESULTS Between December 2010 and May 2011, the operation was performed in 35 patients (10 women; 25 men; age 71.8 years). The average time of surgery was 42 min/segment, the average blood loss was 20.3 ml/segment. Of the 35 patients, 15 did not required wound drainage. All patients were mobilized without restriction after 4-6 h, hospitalization was 5.2 days. There were 3 intraoperative complications (2 Dura lesions [5.7%] and 1 temporary L5 radiculopathy probably due to swelling of the L5 nerve root [2.8%]). Postoperatively there was a significant improvement in quality of life as measured with EQ 5D and Oswestry Disability Index as well as a significant improvement of walking distance and standing time.
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Affiliation(s)
- H M Mayer
- Wirbelsäulenzentrum, Schön Klinik München - Harlaching, Harlachinger Str. 51, 81547, München, Deutschland.
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Abstract
This study addresses the epidemiology of injuries in adolescent male and female soccer players in Germany. Therefore, the purpose of the study was to analyse the injuries in male and female youth soccer players in Germany. This study was designed as a cross-sectional web-based survey. From March until December 2011 we investigated 1110 soccer players (male n = 841; female n = 269) aged 12 - 19 years (15.0 ± 2.0 years) from 60 clubs in Southern Germany. A total of 664 (79 %) of the 841 boys and 67 (25 %) of the 269 girls reported being injured due to soccer. The total number of injuries was 2373. Respectively the frequency of injury was 2.85 in boys and 7.10 in girls. The lower extremities were affected in 70 % of all reported cases. Strains were the most common injuries in the lower and upper extremities (35 %). The boys reported in 51.5 % of all injuries that the injury was non-contact in nature. In contrast, 52.1 % of the injuries in girls were reported as contact injuries. Similar amounts of injuries were observed in training versus games for both genders. Prevention procedures, such as a thorough warm-up, should be implemented before every game and training to reduce the risk of injury.
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Affiliation(s)
- A S Schneider
- Schön Klinik München Harlaching, Rückeninstitut, FIFA Medical Center, München.
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Affiliation(s)
- C Mehren
- Spine Centre Munich, Orthozentrum Munchen, Germany.
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Abstract
Spinal fusion is accepted worldwide as a therapeutic option for the treatment of degenerative disorders of the lumbar spine. Because there are only few evidence-based data available supporting the usefulness of lumbar spinal fusion, its questionable benefit as well as the potential for complications are the reasons for an ongoing discussion. In recent years, total disc replacement with implants has emerged as an alternative treatment. Although early results are promising, there is still a lack of evidence-based data as well as of long-term results for this technology. This article gives a critical update on the implant systems currently in use (SB Charité, Prodisc II L, Maverick, Flexicore, Mobidisc), which all have to be considered as "first-generation" implants. Morphological and clinical sequelae of the different biomechanical properties, designs, and materials have not yet been sufficiently investigated. There is no international consensus on the indication spectrum and on the preoperative diagnosis of discogenic low back pain. The same is true for the (minimally invasive) surgical access strategies. Complication rates seem to be somewhat lower compared to spinal fusion techniques. There are no standardized revision concepts in cases of implant failure. Lumbar disc replacement has opened a new era in spinal surgery with a still unproven benefit for the patient. It is strongly recommended that these techniques should only be applied by experienced and well-trained spine surgeons. Until evidence-based data are available, all patients should be treated under scientific study conditions with close postoperative follow-up.
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Affiliation(s)
- H M Mayer
- Wirbelsäulenzentrum, Orthozentrum, München.
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Abstract
In Germany, lumbar disc herniations require surgical treatment in about 50,000 patients/year. The clinical and socio-economical results are determined by the preoperative duration of symptoms and preoperative time out of work (highly predictive). Other parameters such as severity of neurological deficits, morphology of disc herniation, age, associated diseases, type of surgery, working conditions or litigation processes are only weak predictors of outcome. Postoperative improvement of clinical symptoms as well as professional reintegration is strongly determined by the time period between onset of symptoms and surgery. Surgery performed "too early" diminishes the chance for improvement by conservative therapy. If surgery is performed "too late" the risk of a bad result is high, and the reintegration of the patient into his preoperative social and professional activities may be prevented. The duration of conservative therapy including so-called semi-invasive procedures is critical in this sense. If a therapeutic success (= professional and social reintegration) cannot be achieved by conservative measures and if there is a clear morphological correlate (= disc herniations with corresponding clinical symptoms) of the clinical symptoms an early change of the strategy towards surgical therapy is recommended.
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Affiliation(s)
- H M Mayer
- Wirbelsäulenzentrum München, Orthopädische Klinik -- Orthozentrum München.
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Affiliation(s)
- H M Mayer
- Orthozentrum München, Spine Center Munich, Harlachinger Str. 51, D-81547 München, Germany.
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Mayer HM, List J, Korge A, Wiechert K. [Microsurgery of acquired degenerative lumbar spinal stenosis. Bilateral over-the-top decompression through unilateral approach]. Orthopade 2004; 32:889-95. [PMID: 14579021 DOI: 10.1007/s00132-003-0536-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Degenerative lumbar spinal stenosis is diagnosed with an increasing incidence. Clinical and radiological signs of progression often result in a significant decrease in the patient's quality of life. The indication for surgical treatment follows the spectrum of clinical symptoms. In cases with "structural" spinal stenosis and predominant "leg symptoms" such as neurogenic claudication and/or radicular symptoms, decompressive types of surgery are indicated. However, due to the multimorbidity of the mostly elderly patients, the surgical risk should be as low as possible whereas the surgical efficacy should be as high as possible. We describe a microsurgical technique, which can achieve a bilateral decompression of the central and lateral lumbar spinal canal through a unilateral surgical approach. In a consecutive series of 275 patients, a significant increase in standing time and walking distance could be attained. The surgical complication rate was low. A complete decompression of the spinal canal with preservation of the "tension band" of the posterior spinal column could be achieved. Although this type of surgery is adequate for patients with "predominantly leg symptoms" only, low back pain improved as well in nearly 50% of the patients. However, in cases with dynamic spinal stenosis and/or disturbed curvature with predominant low back pain, a combination of the described procedure with stabilizing surgery (spinal fusion, dynamic fixation etc.) is recommended.
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Affiliation(s)
- H M Mayer
- Wirbelsäulenzentrum München, Orthopädische Klinik, Orthozentrum München, Munich.
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Husson JL, Korge A, Polard JL, Nydegger T, Kneubühler S, Mayer HM. A memory coiling spiral as nucleus pulposus prosthesis: concept, specifications, bench testing, and first clinical results. J Spinal Disord Tech 2003; 16:405-11. [PMID: 12902957 DOI: 10.1097/00024720-200308000-00013] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The intradiscal cavity left after a discectomy can be filled by a new nucleus prosthesis made of polycarbonate urethane in the form of a "memory coiling spiral." Biomechanical tests have demonstrated that this device compensates for the loss of disc height, decreases the compression of the facet joints, and restores the kinematics of the spinal segment, without deformation of the vertebral endplates or migration. The device is currently under clinical investigation. Inclusion and exclusion criteria of the pilot study are presented, and preliminary results of the first five patients supplied with the spiral are reported after an average follow-up time of 24 months. No migration of the device has been observed so far. With its easy application due to the standardized approach and the memory coiling mechanism, this device represents an advance within the nonfusion techniques.
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Affiliation(s)
- J L Husson
- Service orthopédie-traumatologie A, CHU Hôtel Dieu, Rennes, France.
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Mayer HM, Wiechert K, Korge A, Qose I. Minimally invasive total disc replacement: surgical technique and preliminary clinical results. Eur Spine J 2002; 11 Suppl 2:S124-30. [PMID: 12384733 PMCID: PMC3611566 DOI: 10.1007/s00586-002-0446-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2002] [Accepted: 05/10/2002] [Indexed: 11/27/2022]
Abstract
Total disc replacement has become an option for the treatment of degenerative disc disease of the lumbar spine. A new generation of implants has been developed that can be implanted through minimally invasive anterior approaches to the lumbar levels L2/3, L3/4, L4/5 and L5/S1. However mid- and long-term data are still lacking. This paper describes the minimally invasive surgical approach - techniques as well as the preliminary results of our first 34 consecutive patients. The intervertebral spaces L5/S1, L4/5, L3/4 and L2/3 were each approached through slightly different, but standardized, mini-laparotomies either through a retroperitoneal or a transperitoneal route. The clinical results with a follow-up of up to 1 year show satisfactory outcomes in about 80% of the patients. Oswestry score as well as VAS values show significant changes during the postoperative course. There have been three complications (8.8%), two of which were specific to the implantation process, but were resolved with a good clinical outcome in both patients. The preliminary results suggest that total disc replacement may become a reasonable alternative to spinal fusion under the selection criteria used in this study.
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Affiliation(s)
- H M Mayer
- Spine Center, Orthopedic Clinic Munich-Harlaching, Harlachinger Strasse 51, 81547 Munich, Germany.
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Korge A, Nydegger T, Polard JL, Mayer HM, Husson JL. A spiral implant as nucleus prosthesis in the lumbar spine. Eur Spine J 2002; 11 Suppl 2:S149-53. [PMID: 12384737 PMCID: PMC3611576 DOI: 10.1007/s00586-002-0444-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2002] [Accepted: 05/10/2002] [Indexed: 10/25/2022]
Abstract
Microdiscectomy represents the gold standard in disc surgery on the lumbar spine. The remaining defect in the intervertebral disc space can be filled with a newly developed nucleus prosthesis presented in this paper. This prosthesis consists of polycarbonate urethane (Sulene PCU), and takes the form of a memory coiling spiral. It can be easily implanted using the standard microdiscectomy approach with no further tissue damage. Biomechanical tests have shown that anatomical distances can be restored by the spiral for both the facet joints and the endplates. Endplate deformations are not statistically different when compared to intact conditions. Inclusion and exclusion criteria of an in vivo pilot study are presented. The paper describes the insertion setup for the spiral and the technique of implantation. Five patients have been supplied with the implant to date. The first results on postoperative magnetic resonance images are presented.
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Affiliation(s)
- A Korge
- Spine Center, Orthopedic Clinic Munich-Harlaching, Harlachinger Strasse 51, 81547 Munich, Germany.
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Abstract
Surgery in acute and/or chronic low back pain is still a matter of intensive and controversial discussions. A vast number of minimally invasive or so called semi-invasive procedures have been published in the last 3 decades, but evidence-based data on efficacy and benefit of most of these techniques are still lacking. However, empirical data suggest good or at least satisfactory clinical results for a limited number of procedures if they are applied under restrictive indication criteria. Discogenic low back pain and lumbar spinal stenosis belong to the most frequent diagnoses associated with low back pain. This article gives a survey on definitions, indication criteria and modern surgical or semi- invasive techniques used for the treatment of these two pathologic entities. Discogenic low back pain: This clinical and morphological entity is defined as low back pain arising mainly from disc degeneration. Pain generators are usually nociceptors in the cartilaginous endplates, in the outer anulus fibrosus as well as in the periosteum of the vertebral bodies. Clinical symptoms correlate with morphologic changes detected with MR-imaging (modic type I) or with contained disc protrusions mainly without neurological symptoms. Surgery is rarely indicated, spontaneous remissions occur in more than 60% of all cases. Spinal fusion has been the only surgical option in cases which did not respond to conservative therapy. Recently, electro-thermal modulation of the posterior anulus fibrosus has been published as a semi- invasive technique to relieve low back pain generated by fissures in the outer anulus and ingrowing nociceptors (intradiscal electro-thermal therapy, IDET(TM)). First results are promising, however, prospective randomised studies comparing this technique with conservative therapy are still lacking. The same is true for artificial nucleus pulposus replacement using hydrogel cushions implanted in the intervertebral space after removal of the nucleus pulposus from posterior or through an anterior approach (PDN, prosthetic disc nucleus(TM)). In cases with severe disc degeneration total disc replacement is another innovative option (ProDisc(TM)). Two metal endplates with titanium surface coating are implanted through a minimal invasive anterior approach (mini-laparotomy). A polyethylene inlay anchored in the caudal endplate holds the distance between the endplates and preserves the physiological range of motion between the two vertebral bodies. Degenerative lumbar spinal stenosis: Narrowing of the spinal canal due to degenerative changes of the disc, the facet joints and thickening of the yellow ligament is a geriatric disease which is diagnosed in increasing numbers within the last 10 years. More than 80% of the patients present with low back pain in association with neurogenic claudication. Neurological symptoms at rest are less frequently found. The spontaneous course shows progressive symptoms in more than 50% of all patients. More than 35% of the patients have associated diseases which might influence the perioperative course, complication rates and outcomes of surgery. Surgery is indicated in patients with progressive neurological symptoms, unacceptable decrease of quality of life or progressive intractable pain. In patients with mainly "leg symptoms" microsurgical mono- or multisegmental decompression is the procedure of choice. If low back pain is predominant and associated with degenerative instability such as degenerative spondylolisthesis or lumbar scoliosis, decompression must be combined with instrumented spinal fusion. In general a restrictive indication for surgery must be recommended especially for spinal fusion procedures. Non-fusion techniques such as intradiscal electro thermal therapy or spine arthroplasty with replacement of nucleus pulposus or total disc show promising early results; however, little is known about the long-term effect. It should be a principle to apply surgery in the least invasive way.
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Affiliation(s)
- H M Mayer
- Orthopädische Klinik München-Harlaching/Wirbelsäulenzentrum, München.
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Mayer HM. [Revolution in spinal surgery. What is the value of intervertebral disk prostheses? (interview by Waldtraut Paukstadt)]. MMW Fortschr Med 2001; 143:9. [PMID: 11460428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Abstract
A 17-year-old patient with pre-existing grade II spondylolisthesis of L5/S1 sustained a partial disruption of the left sacroiliac joint with haematoma of the iliac muscle after a fall. The haematoma probably led to occlusion of the left ureter, resulting in a urinary tract infection. After initial conservative treatment the patient developed fever and radicular pain of the left leg. Magnetic resonance imaging (MRI) revealed a left-sided epidural abscess at L5/S1, which had probably spread from the infected iliac haematoma along the injured sacroiliac joint. Prompt surgical drainage and antibiotic coverage with cefuroxime and flucloxacillin led to rapid clinical improvement. Staphylococcus aureus was identified as the pathogen. At follow-up 6 months postoperatively all symptoms had resolved, while MRI still revealed residual osseous oedema of the sacroiliac joint. The haematoma of the iliac muscle resolved without surgical intervention.
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Affiliation(s)
- B M Boszczyk
- Spine Centre, München-Harlaching Orthopaedic Hospital, Munich, Germany.
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Abstract
The terms 'minimally invasive' or 'less invasive surgery' have been used recently to describe surgical approaches or operations that are performed with less trauma to anatomical structures on the way to or surrounding the surgical 'target area'. These types of surgical procedures are usually performed with the help of 'high-tech' instruments such as surgical endoscopes or surgical microscopes, modern video techniques and automated instruments. Within the last 10 years, such techniques have been developed in the field of spinal surgery. The application of minimally or less invasive procedures has concentrated predominantly on anterior approaches to the thoracic and lumbar spine. This article describes two anterior approach techniques for performing anterior lumbar interbody fusion (ALIF) through a minimally invasive retroperitoneal or transperitoneal approach. The technical principles are microsurgical modifications of traditional anterior approaches to the lumbar spine. Through small (4-cm) skin incisions, the target area can be exposed. Preliminary results suggest decreased peri - and postoperative morbidity, less blood loss, earlier rehabilitation and acceptable complication rates. The technique is currently used by the author for all patients requiring anterior lumbar interbody fusion.
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Affiliation(s)
- H M Mayer
- Orthopädische Klinik, München-Harlaching, Munich Spine Center, Germany.
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Rohlmann A, Bergmann G, Graichen F, Mayer HM. Placing a bone graft more posteriorly may reduce the risk of pedicle screw breakage: analysis of an unexpected case of pedicle screw breakage. J Biomech 1998; 31:763-7. [PMID: 9796678 DOI: 10.1016/s0021-9290(98)00073-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Telemeterized internal spinal fixation devices were implanted in a patient with degenerative instability and a narrow spinal canal in order to measure the fixator loads during daily activities. Anterior interbody fusion was performed three weeks later. During walking, the typical maximum flexion bending moments were 10 N m in the left and 5 N m in the right fixator. On removal of the implants three months later, a fatigue fracture was found not on the high loaded left side but in the upper right pedicle screw. The crack started on the caudal side of the cross-sectional area and progressed cranially. Upper vertebral tilting in the sagittal plane must have caused the screw breakage. This would probably have been prevented by a more posteriorly placed bone graft.
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Affiliation(s)
- A Rohlmann
- Biomechanics Laboratory, Oskar-Helene-Heim, Biomechanik-Labor, Berlin, Germany.
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21
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Abstract
STUDY DESIGN The loads acting on an internal spinal fixation device were measured in vivo. OBJECTIVES To determine the influence of muscle forces on implant loads. SUMMARY OF BACKGROUND DATA Only limited information exists regarding the loads acting on spinal implants in vivo. Though the muscles greatly influence spinal load, they have been neglected in most studies. METHODS Telemeterized internal spinal fixation devices were used to study the influence of muscle forces on the implant loads in three patients before and after anterior interbody fusion. RESULTS Contracting abdominal or back muscles in a lying position was found to significantly increase implant loads. Hanging by the hands from wall bars as well as balancing with the hands on parallel bars reduced the implant loads compared with standing; however, hanging by the feet with the head upside down did not reduce implant loads compared with lying in a supine position. When lying on an operating table with only the foot end lowered so that the hips were bent, the patient had different load measurements in the conscious and anesthetized state before anterior interbody fusion. The anesthetized patient evidenced predominately extension moments in both fixators, whereas flexion moments were observed in the right fixator of the conscious patient. After anterior interbody fusion had occurred, the differences in implant loads resulting from anesthesia were small. CONCLUSIONS The muscles greatly influence implant loads. They prevent an axial tensile load on the spine when part of the body weight is pulling, e.g., when the patient is hanging by his hands or feet. The implant loads may be strongly altered when the patient is under anesthesia.
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Affiliation(s)
- A Rohlmann
- Department of Biomechanics, Free University of Berlin, Germany
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22
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Schwetlick G, Mayer HM. [Not Available]. Oper Orthop Traumatol 1997; 9:317-23. [PMID: 17004144 DOI: 10.1007/s00064-006-0105-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Affiliation(s)
- G Schwetlick
- Orthopädische Klinik der Pfeifferschen Stiftung Magdeburg, Pfeifferstraße 10, D-39114, Magdeburg
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23
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Abstract
STUDY DESIGN A series of patients were prospectively studied to determine the morbidity and possible complications of minimally invasive anterior lumbar interbody fusion by two new microsurgical approaches (retroperitoneal for segments L2-L3, L3-L4, and L4-L5, and transperitoneal for L5-S1). OBJECTIVES To investigate the feasibility of performing an anterior lumbar interbody fusion through a 4-cm skin incision and a standardized muscle-splitting approach. SUMMARY OF BACKGROUND DATA The utility of anterior lumbar interbody fusion with or without posterior instrumentation for the treatment of various degenerative or postoperative lesions associated with low back pain is still a matter of debate. Regardless of the indications for surgery, use of the anterior approach in the lumbar spine is known to be associated with considerable surgical trauma, a high postoperative morbidity, and, occasionally, unacceptably high complication rates. Laparoscopic anterior interbody fusion of L5-S1 to eliminate some of these problems has been recently described. However, a minimally invasive surgical concept that covers all lumbar segments from L2 to S1 has not been described before now. METHODS A standardized, microsurgical retroperitoneal approach to levels L2-L3, L3-L4, and L4-L5 and a microsurgical transperitoneal approach through a "minilaparotomy" to L5-S1 are described. The first 25 patients (retroperitoneal, n = 20; transperitoneal, n = 5) treated with these methods are evaluated with respect to intraoperative data such as blood loss, operating time, intraoperative and postoperative complications, as well as preliminary fusion results. RESULTS There were no general or technique-related complications in the first series of 25 patients. Postoperative morbidity was low in all patients, with negligible wound pain. Average blood loss was 67.8 ml for the retroperitoneal technique and 168 ml for the transperitoneal approach. No blood transfusion was necessary. All patients showed solid bony fusion. CONCLUSIONS The microsurgical approaches described in this article are atraumatic techniques to reach the lumbar spinal levels L2-L3, L3-L4, L4-L5, and L5-S1. They represent microsurgical modifications of the surgical approaches well known to the spine surgeon. They can be learned in a step-by-step fashion, starting with a conventional skin incision and, once the surgeon is familiar with the instruments, moving on to the microsurgical technique. The approaches are not restricted to the type of fusion (iliac crest autograft) presented in this series.
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Affiliation(s)
- H M Mayer
- Department of Orthopedic Surgery, Freie Universität Berlin, Oskar-Helene-Heim, Germany
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24
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Mayer HM, Weber U. [SICOT '95. Current developments in spinal surgery. Amsterdam 8-18-23, 1996]. Orthopade 1997; 26:81-4. [PMID: 9082308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- H M Mayer
- Orthopädische Universitäts-Klinik und Poliklinik, Oskar-Helene Heim, Berlin
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25
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Rohlmann A, Calisse J, Bergmann G, Radvan J, Mayer HM. Clamping stiffness and its influence on load distribution between paired internal spinal fixation devices. J Spinal Disord 1996; 9:234-40. [PMID: 8854279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The load distribution between two internal spinal fixation devices depends, besides other factors, on their stiffness. The stiffness ranges were determined experimentally for the clamps of the AO internal fixator with lateral nut and with posterior nut as well as for the clamps of the SOCON fixator. The stiffness of eight devices each differed by a factor of 3.1 for the clamp with lateral nut, by a factor of 1.5 for the clamp with posterior nut, and by a factor of 1.4 for the clamp of the SOCON fixator. For the AO clamp with lateral nut, the influence of the nut-tightening torque on the stiffness was determined. Using instrumented internal spinal fixation devices mounted to plastic vertebrae and simulating a corpectomy, the load distribution between the implants was measured for different tightening torques. It could be shown that, for the AO internal fixator whose clamps have a lateral nut, a nut-tightening torque > 5 Nm has only a negligible influence on load-sharing between the implants. Tooth damage occurs when the teeth of the clamp body and clamping jaw of the clamp with lateral nut do not gear together exactly, which leads to changes in the clamping stiffness and load-sharing between the two implants.
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Affiliation(s)
- A Rohlmann
- Department of Biomechanics, Free University of Berlin, Oskar-Helene-Heim, Germany
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26
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Mayer HM, Mellerowicz H, Dihlmann SW. Endoscopic discectomy in pediatric and juvenile lumbar disc herniations. J Pediatr Orthop B 1996; 5:39-43. [PMID: 8744431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Most herniated lumbar discs in children and adolescents respond to conservative treatment, but some young patients with persistent low back and neurological symptoms do not respond to noninvasive treatment and require operative treatment. Because the long-term results of disc surgery depend not only on the disc disease itself but also on the degree of surgical trauma, disc herniations in children and adolescents should be treated with minimally invasive procedures. We report our experience with four young patients aged 8-17 years with contained or small noncontained lumbar disc herniations who were treated by percutaneous endoscopic discectomy (PED). The clinical results were good to excellent in all four cases, with follow-up of 1 to 5 years. There were no complications, and the operation was tolerated well by the young patients. We recommend percutaneous endoscopic lumbar discectomy in patients with contained or small uncontained disc herniations who do not respond to conservative treatment.
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Affiliation(s)
- H M Mayer
- Department of Orthopaedic Surgery, Oskar-Helene-Heim, Free University of Berlin, Germany
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27
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Rohlmann A, Bergmann G, Graichen F, Mayer HM. Telemeterized load measurement using instrumented spinal internal fixators in a patient with degenerative instability. Spine (Phila Pa 1976) 1995; 20:2683-9. [PMID: 8747246 DOI: 10.1097/00007632-199512150-00009] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN In the present study, the loads in an internal spinal fixation device were measured in vivo. OBJECTIVES To determine the implant loads for different activities before and after additional anterior stabilization of the spine. SUMMARY OF BACKGROUND DATA Mathematical models exist for predicting spinal loads. The intradiscal pressure has been measured for many body positions and activities. The loads on internal spinal fixation devices have not been measured before in vivo. METHODS Telemeterized AO spinal internal fixators were implanted in a patient with degenerative instability. The implants allow the in vivo measurement of three force components and three moments acting in the implant. RESULTS When the patient was lying in relaxed positions, the implant loads were small. Before additional anterior stabilization, the loads were also small for sitting, standing, and walking. The bending moment in the sagittal plane was less than 3 Nm for these activities. The highest loads within the first 4 weeks after implantation were measured while the patient turned from a supine to a lateral position against the advice of the physiotherapist. After anterior stabilization, the maximum loads for the relaxed lying positions were altered only slightly. Much higher axial forces and bending moments were measured for sitting, standing, and walking. The maximum bending moment increased to 5-8 Nm for these activities. The implant loads for sitting were not higher than for standing. CONCLUSION Flexion and lateral bending of the upper body and weight-carrying during sitting, standing, or walking should be avoided in the first few months after anterior stabilization.
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Affiliation(s)
- A Rohlmann
- Department of Biomechanics, Free University Berlin, Germany
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28
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Schulze CJ, Mayer HM. Exogenous lumbar spondylodiscitis following a stabwound injury and vertebral fracture. A case report and review of the literature. Eur Spine J 1995; 4:357-9. [PMID: 8983656 DOI: 10.1007/bf00300297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Exogenous spondylodiscitis is a rare event and is usually iatrogenic. Non-iatrogenic exogenous spondylodiscitis has been described in the literature following transabdominal gunshot wounds associated with injury to the intestines and spine. Several cases of traumatic meningitis and one of a traumatic meningocele following an injury of the spinal sac have been reported. No report of exogenous spondylodiscitis complicating a stabwound has been published. This is a report of exogenous spondylodiscitis following a paravertebral stabwound with a knife in association with a superior wedge fracture of L2.
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Affiliation(s)
- C J Schulze
- Department of Orthopaedic Surgery, Free University of Berlin, Germany
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29
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Ricke J, Kleinholz L, Hosten N, Schedel H, Gentz P, Vöge KH, Kanzow J, Dihlmann W, Mayer HM, Weber U. [Technique and economics of first worldwide roentgen conference via public phone lines with the Medical Desktop-Conference and Integrated Services Digital Network]. Aktuelle Radiol 1995; 5:346-50. [PMID: 8580130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The introduction of the world's first Medical Desktop-Conference via public phone lines (ISDN-S2M) in spring 1994 for the weekly discussion of radiological findings with 25 orthopedic surgeons has proved the effectiveness of this system developed by the project BERMED. The use of standard hard- and software as well as ISDN are the most important factors to keep the system costs low. Technical advantages can be seen in the immediate, loss-free transmission of image and other patient-related data and in the integration of digital archives. Medical advantages are the 24-hour-availability of the radiologist and quality-control of the radiologists work. Practitioners and external hospitals can be tied closely to radiological service centers by using ISDNetwork.
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Affiliation(s)
- J Ricke
- Strahlenklinik und Poliklinik Virchow-Klinikum, Medizinischen Fakultät, Humboldt-Universität zu Berlin
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30
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Dihlmann SW, Mayer HM. [Lumbar epidural lipomatosis]. Z Rheumatol 1995; 54:417-23. [PMID: 8578893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Spinal epidural lipomatosis is a pathological accommodation of fat tissue in the spinal canal. It seems to be a disease entity, which, though rare, has recently been diagnosed more frequently and can be accompanied by neurological deficits. The thoracic spinal canal is the preferred localization. Eighteen cases of symptomatic lumbar epidural lipomatosis have been described in the literature. We are reporting on our experience with another 8 patients. Three of these patients presented with the typical signs of spinal nerve irritation. In these cases epidural lipomatosis was associated with a small disk herniation without direct contact to the spinal nerve. Another 5 patients showed the clinical picture of a spinal claudication. In all 5 patients, there was a concentric compression of the thecal sac by epidural fat. In one patient, the cause of the lipomatosis was assumed to be long-term steroid therapy following kidney transplantation. Four patients suffered from extreme obesity. No cause for lipomatosis could be found in 3 patients. A microdiskektomy was performed in the 3 patients with the associated disk herniation; the remaining patients were treated conservatively. In 6/8 patients (3x surgery/3x diet), an "excellent" or "good" clinical result could be achieved after 1 year. Two patients had a "satisfactory" result. Lumbar epidural lipomatosis can be treated conservatively in cases with only mild neurological dysfunctions and known cause (e.g. obesity, steroid therapy). The surgical removal of associated disk herniation proved to be sufficient in cases described in this paper.
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Affiliation(s)
- S W Dihlmann
- Orthopädische Klinik und Poliklinik Freie Universität Berlin
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31
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Hosten N, Lemke AJ, Mayer HM, Dihlmann SW, Pichler E, Felix R. [Spondylitis: borderline findings in magnetic resonance tomography]. Aktuelle Radiol 1995; 5:164-8. [PMID: 7605814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
MR studies of 41 patients with confirmed spondylitis were evaluated with regard to imaging findings resembling metastases or fracture. 30 patients had MR results considered typical for spondylitis (contiguous changes in two vertebrae and disc, soft tissue tumour). 11 patients had MR studies differing from this pattern. Absence of soft tissue involvement and discontinuous marrow changes may be misdiagnosed as bone marrow metastases.
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Affiliation(s)
- N Hosten
- Strahlenklinik und Poliklinik, Klinikum Rudolf Virchow, Freie Universität Berlin
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32
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Abstract
Clinical and radiological examination of 167 hemispherical spondylosclerosis (HSS) patients (56 male, 111 female) revealed a total of 186 cases of HSS with multiple incidences occurring in 18 patients. Radiologically these HSS cases were characterized by erosion and new bone formation at the inferior and upper end plate of the vertebra below, periosteal bone apposition or ossification of the anterior longitudinal ligament, spondylophytes, and signs of degenerative alteration of the vertebra and disc. In addition, the size and location (anterior, middle, posterior third) of each HSS in the lateral view was investigated. The cases were also investigated for reflection phenomenon between supra- and infradiscal sclerosis and for kyphotic angulation of the two adjacent vertebrae. The results showed that in 105 cases (56.5%) the HSS filled out the entire vertebral area; 97 cases (52.2%) showed a mirror-image type HSS; while in 8 cases (4.3%), the infradiscal sclerosis was polymorphic. In 81 cases (43.5%), the sclerosis was limited to the anterior two-thirds; this is termed "two-thirds" type. All 81 of these cases of HSS showed a kyphotic angulation of at least 4 degrees. Of these, 61 (32.8% of the total) showed reflection phenomenon while 20 (10.7% of the total) had polymorphic infradiscal sclerosis. Overall, 158 cases of HSS (85%) exhibited the reflection phenomenon between supra- and infradiscal sclerosis, whereas 28 cases (15%) revealed polymorphic sclerosis of the subadjacent vertebra. Kyphotic angulation was completely absent when HSS was visible in the entire vertebra. A dorsal gap of the disc space was seen in 36 cases (19.4%).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S W Dihlmann
- Department of Orthopedic Surgery, Free University, Berlin, Germany
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33
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Mayer HM. Spine update. Percutaneous lumbar disc surgery. Spine (Phila Pa 1976) 1994; 19:2719-23. [PMID: 7899970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Various techniques of percutaneous lumbar disc surgery have become popular for treating lumbar disc herniations. There is a vast and increasing body of literature on this topic that consists mainly of retrospective, uncontrolled clinical studies, technical articles, and case reports. A literature analysis revealed two different techniques, both termed "percutaneous discectomy." One is the selective removal of nucleus pulposus from the herniation site with various manual and automated instruments under endoscopic control (percutaneous nucleotomy with discoscopy, arthroscopic microdiscectomy, percutaneous endoscopic discectomy); the other is the removal of nucleus pulposus from the center of the disc space with one single automated instrument (automated percutaneous lumbar discectomy) to achieve an intradiscal decompression. Selective percutaneous discectomy with endoscopic control requires a restrictive selection of patients and can achieve clinical results comparable with microdiscectomy under controlled conditions. There is no scientifically proven validity of automated percutaneous lumbar discectomy compared with standard surgical methods and chemonucleolysis. The majority of the articles analyzed did not fulfill the selection criteria of Spine. Additional prospective, randomized and controlled studies are needed to define the eventual role of percutaneous lumbar discectomy on a scientific basis.
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Affiliation(s)
- H M Mayer
- Department of Orthopaedic Surgery, Oskar-Helene-Heim, Free University of Berlin, Germany
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34
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Schubeus P, Sander B, Hosten N, Mayer HM, Weber U, Felix R. [MRT in degenerative diseases of the cervical spine]. Aktuelle Radiol 1994; 4:12-15. [PMID: 8136384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
MRI has grown increasingly important in recent years in diagnosis of degenerative disease of the cervical spine, due to improvements of method that have made it a valuable diagnostic tool. The following contribution gives a brief introduction to the pathophysiology of degenerative changes in the cervical vertebral column and to the indications for MRI, describing within the framework of imaging the present state of MR examination technique. The ranking of the various gradient echo sequences, of the 3D methods and of the administration of contrast media in cervical myelopathy and radiculopathy is discussed.
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Affiliation(s)
- P Schubeus
- Strahlenklinik mit Poliklinik, Universitätsklinikum Rudolf Virchow, Berlin
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35
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Mayer HM. Conventional discectomy. Spine (Phila Pa 1976) 1993; 18:1562-3. [PMID: 8235831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Abstract
Percutaneous endoscopic discectomy is a new technique for removing "contained" lumbar disc herniations (those in which the outer border of the anulus fibrosus is intact) and small "noncontained" lumbar disc herniations (those at the level of the disc space and occupying less than one-third of the sagittal diameter of the spinal canal) through a posterolateral approach with the aid of specially developed instruments. The technique combines rigid straight, angled, and flexible forceps with automated high-power suction shaver and cutter systems. Access can thus be gained to the dorsal parts of the intervertebral space where the disc herniation is located. Percutaneous endoscopic discectomy is monitored using an endoscope angled to 70 degrees coupled with a television and video unit and is performed with the patient under local anesthesia and an anesthesiologist available if needed. Its indication is restricted to discogenic root compression with a minor neurological deficit. Two groups of patients with contained or small noncontained disc herniations were treated by either percutaneous endoscopic discectomy (20 cases) or microdiscectomy (20 cases). Both groups were investigated in a prospective randomized study in order to compare the efficacy of the two methods. The disc herniations were located at L2-3 (one patient), L3-4 (two patients), or L4-5 (37 patients). There were no significant differences between the two groups concerning age and sex distribution, preoperative evolution of complaints, prior conservative therapy, patient's occupation, preoperative disability, and clinical symptomatology. Two years after percutaneous endoscopic discectomy, sciatica had disappeared in 80% (16 of 20 patients), low-back pain in 47% (nine of 19 patients), sensory deficits in 92.3% (12 of 13 patients), and motor deficits in the one patient affected. Two years after microdiscectomy, sciatica had disappeared in 65% (13 of 20 patients), low-back pain in 25% (five of 20 patients), sensory deficits in 68.8% (11 of 16 patients), and motor deficits in all patients so affected. Only 72.2% of the patients in the microdiscectomy group had returned to their previous occupation versus 95% in the percutaneous endoscopic discectomy group. Percutaneous endoscopic discectomy appears to offer an alternative to microdiscectomy for patients with "contained" and small subligamentous lumbar disc herniations.
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Affiliation(s)
- H M Mayer
- Department of Neurosurgery, Universitaetsklinikum Steglitz, Freie Universitaet Berlin, Germany
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37
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Abstract
Chemonucleolysis was unsuccessful in 100 out of 519 patients with herniated lumbar discs treated within a period of 3 years. These patients were subsequently submitted to open surgery. Disc material from 88 of the 100 patients was examined by light microscopy (hematoxylin and eosin, van Gieson's, Nissl's and periodic acid-Schiff staining) to verify the effect of enzymatic activity compared to the histologic findings in a similar control group. In 84 of the 88 cases, signs of enzymatic activity were revealed by eosinophilia of the ground substance, altered Nissl staining and positive periodic acid-Schiff reaction within the chondrocyte halos. These alterations indicate that the enzyme was active and confirm the results of previous studies with smaller numbers of cases. Histologic alterations were quantified according to the intensity and extent of staining. The signs of enzymatic activity were significantly (P < 0.01) stronger after short time intervals between chemonucleolysis and surgery than after long intervals. These findings may be interpreted as indicating a regenerative potential of the nucleus pulposus.
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Affiliation(s)
- S Patt
- Department of Neurosurgery, Klinikum Steglitz, Free University of Berlin, Germany
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38
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Affiliation(s)
- H M Mayer
- Department of Orthopedic Surgery, Free University of Berlin, Germany
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39
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Abstract
Percutaneous endoscopic lumbar discectomy (PELD) is a new technique for the decompression of the lumbar disc space and removal of nucleus pulposus via a posterolateral approach. The technique was introduced in Germany by the authors in April 1987. The method is indicated in patients with nonsequestrated lumbar disc herniation with an intact dorsal longitudinal ligament. In local anesthesia, a working cannula (OD 5 mm) is placed at the dorsal lateral border of the disc. The disc space is opened with anulus trephines and the nucleus pulposus is removed with rigid and flexible forceps as well as with automated shaver systems under intermittent endoscopic control (discoscopy). The procedure is performed in local anesthesia. The results of the first thirty patients with a follow-up time between 6 months and 17 months could be graded as excellent in 13 cases, as good in 9 cases, as fair in 6 cases, and as bad in 2 cases. The relief of symptoms as judged by the patients was between 70-100 percent in the majority of the cases. Three patients had to be reoperated at the same level and site, because of either persistent or recurrent sciatica. The performance in local anesthesia, the atraumatic extraspinal approach, the reduced time of hospitalization and postoperative morbidity as well as the reduced time of work incapability are the main advantages of this new method.
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Affiliation(s)
- H M Mayer
- Department of Neurosurgery, Klinikum Steglitz, Free University of Berlin, Fed. Rep. of Germany
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40
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Abstract
There are no detailed data in literature concerning the histologic nature of the sequestered (extruded) lumbar disc, and on the frequency with which an extruded fragment, a prolapse or a protrusion are found at surgery. A prospective analysis of 100 consecutive cases of sequestered lumbar disc herniation submitted to surgical treatment revealed this group to represent 28.6% of all cases operated on for lumbar disc herniation. Patients (both male and female) with sequestered lumbar discs are significantly older than those with prolapsed (P < 0.01) and protruded (P < 0.001) discs. Single extruded fragments (n = 68) were twice as frequent as multiple ones (n = 32). The general belief that a 'sequestered (extruded) disc' is almost invariably composed of nucleus pulposus is not substantiated by this study: In 54 cases the extruded fragment consisted predominantly of nucleus material, whereas in 44 cases it consisted mainly of end-plate material. Multiple as well as recurrent sequestered fragments almost always consist of end-plate material. These findings may reflect the result of metabolic alterations in the course of disc degeneration.
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Affiliation(s)
- M Brock
- Department of Neurosurgery, Klinikum Steglitz, Free University of Berlin, Germany
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41
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Mayer HM, Brock M, Berlien HP, Weber B. Percutaneous endoscopic laser discectomy (PELD). A new surgical technique for non-sequestrated lumbar discs. Acta Neurochir Suppl (Wien) 1992; 54:53-8. [PMID: 1595409 DOI: 10.1007/978-3-7091-6687-1_7] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Basic features and techniques of percutaneous endoscopic laser discectomy are described and the results in 6 patients reported. Indications are: discogenic radicular symptoms, caused by disc protrusions, which do not respond to conservative treatment. Contra-indications are: major neurological deficit, segmental instability and spondylolisthesis, extruded disc prolapse, narrow spinal canal or lateral recess.
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Affiliation(s)
- H M Mayer
- Neurochirurgische Klinik, Universitätsklinikum Steglitz, Freie Universität Berlin, Federal Republic of Germany
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42
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Abstract
A group of 100 patients submitted to microsurgical treatment for herniated lumbar disc following unsuccessful chemonucleolysis with chymopapain were retrospectively compared to a statistically comparable group of patients primarily submitted to microsurgery. This comparison demonstrated that previous unsuccessful chemonucleolysis has no influence on either the short-term or the long-term results of subsequent microsurgery.
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Affiliation(s)
- M Brock
- Department of Neurosurgery, Free University of Berlin, Federal Republic of Germany
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43
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Abstract
We present a 24-year-old patient with multiple chondromas of both hands, the pelvis, the left leg, and an associated brain stem glioma. There was no evidence of hemangioma or dyschromia, and the condition was diagnosed as Ollier's disease, a special type of dyschondroplasia like Maffucci's syndrome and Kast's disease. An increased overall risk for development of malignant skeletal and nonskeletal tumors is associated with Maffucci's syndrome. The risk of malignant degeneration is lower in Ollier's disease. A glioma in the pons and the right lobe of the cerebellum was found in this patient. The literature describes an association with gliomas in only 12 cases of dyschondroplasia and an infratentorial localization in just one case. Signs of malignancy were histologically confirmed in 7 cases without significant preponderance of any one type. Our patient had a low-grade brain stem astrocytoma with fibrillar and gemistocytic components. A stereotactic serial biopsy made it possible to rule out malignant degeneration. Stereotactic brain tumor biopsy as a routine neurosurgical procedure is particularly valuable for deep space-occupying processes and forms the basis for therapy. In the present case, irradiation was not recommended.
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Affiliation(s)
- S Patt
- Institute of Neuropathology, Free University Berlin, Federal Republic of Germany
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44
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Söldner FX, Müller ER, Wagner F, Bosch HS, Eberhagen A, Fahrbach HU, Fussmann G, Gehre O, Gentle K, Gernhardt J, Gruber O, Herrmann W, Janeschitz G, Kornherr M, Krieger K, Mayer HM, McCormick K, Murmann HD, Neuhauser J, Nolte R, Poschenrieder W, Röhr H, Steuer K, Stroth U, Tsois N, Verbeek H. Improved comfinement in high-density ohmic discharges in ASDEX. Phys Rev Lett 1988; 61:1105-1108. [PMID: 10039520 DOI: 10.1103/physrevlett.61.1105] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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45
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Abstract
Intervertebral lumbar disk herniation in children and adolescents is rare. The incidence varies between 0.8% and 3.8% of all disks treated surgically. The uncertainty concerning operative or conservative treatment of this rare clinical entity has led to considering the use of atraumatic techniques, such as chemonucleolysis or percutaneous diskectomy. We report the unusual case of an 11-year-old girl with herniated disk at the L4-5 level treated by percutaneous diskectomy. This is, to our knowledge, the first case of a child treated by this technique. The technical simplicity, the minimal trauma it causes, and the excellent clinical result show that percutaneous diskectomy is a reasonable therapeutic alternative in the treatment of juvenile disks.
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Affiliation(s)
- H M Mayer
- Department of Neurosurgery, University Clinic Steglitz, Free University of Berlin, Federal Republic of Germany
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46
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Mayer HM, Wolff R, Mellerowicz H, Brock M. [Neurinoma of the L3 spinal nerve root as a cause of stress-induced lumbo-ischialgias]. Sportverletz Sportschaden 1988; 2:35-8. [PMID: 3242151 DOI: 10.1055/s-2007-993665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Degenerative diseases of the lumbar vertebral discs or the vertebral joints are the main causes of low back pain and sciatica following overstraining during sports activities. However, they are rarely seen in sportsmen engaged in competitive sports because these persons are mostly young and well-trained. Other neurological diseases are even rarer as possible causes of sciatica. That is why we report on a young athletic who is a short-distance hurdler (110m hurdle race) and has been suffering from a neurinoma of the spinal nerve root L3 with sciatica and pain in the knee as initial symptoms. Attention is drawn to the importance of neurological examinations as part of medical examinations conducted by sports physicians for the purpose of obtaining an overall guiding picture of the subjects' health status.
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Affiliation(s)
- H M Mayer
- Neurochirurgische Klinik, Klinikum Steglitz der Freien Universität, Berlin
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47
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Steinmetz K, Noterdaeme J, Wagner F, Wesner F, Bäumler J, Becker G, Bosch HS, Brambilla M, Braun F, Brocken H, Eberhagen A, Fritsch R, Fussmann G, Gehre O, Gernhardt J, Glock E, Gruber O, Haas G, Hofmann J, Hofmeister F, Izvozchikov A, Janeschitz G, Karger F, Keilhacker M, Klüber O, Kornherr M, Lackner K, Lisitano G, Mast F, Mayer HM, McCormick K, Meisel D, Mertens V, Müller ER, Murmann H, Niedermeyer H, Poschenrieder W, Puri S, Rapp H, Röhr H, Ryter F, Schmitter K, Schneider F, Setzensack C, Siller G, Smeulders P, Söldner F, Speth E, Steuer K, Vollmer O, Wedler H, Zasche D. Observation of a high-confinement regime in a tokamak plasma with ion cyclotron resonance heating. Phys Rev Lett 1987; 58:124-127. [PMID: 10034609 DOI: 10.1103/physrevlett.58.124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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48
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Söldner FX, McCormick K, Eckhartt D, Kornherr M, Leuterer F, Bartiromo R, Becker G, Bosch HS, Brocken H, Derfler H, Eberhagen A, Fussmann G, Gehre O, Gernhardt J, Gierke G, Giuliana A, Glock E, Gruber O, Haas G, Hesse M, Hofmann J, Izvozchikov A, Janeschitz G, Karger F, Keilhacker M, Klüber O, Lackner K, Lenoci M, Lisitano G, Mast F, Mayer HM, Meisel D, Mertens V, Müller ER, Münich M, Murmann H, Niedermeyer H, Pietrzyk A, Poschenrieder W, Rapp H, Riedler H, Röhr H, Ryter F, Schmitter KH, Schneider F, Setzensack C, Siller G, Smeulders P, Speth E, Steuer K, Vien T, Vollmer O, Wagner F, Woyna F, Zasche D. Suppression of sawtooth oscillations by lower-hybrid current drive in the ASDEX tokamak. Phys Rev Lett 1986; 57:1137-1140. [PMID: 10034257 DOI: 10.1103/physrevlett.57.1137] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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49
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Wagner F, Gruber O, Lackner K, Murmann HD, Speth E, Becker G, Bosch HS, Brocken H, Cattanei G, Dorst D, Eberhagen A, Elsner A, Erckmann V, Fussmann G, Gehre O, Gernhardt J, Gierke G, Glock E, Grieger G, Grigull P, Haas G, Hacker H, Hartfuss HJ, Jäckel H, Jaenicke R, Janeschitz G, Junker J, Karger F, Kasparek W, Keilhacker M, Kick M, Klüber O, Kornherr M, Kroiss H, Kuehner M, Lenoci M, Lisitano G, Maassberg M, Mahn C, Marlier S, Mayer HM, McCormick K, Meisel D, Mertens V, Müller ER, Müller G, Niedermeyer H, Ohlendorf W, Poschenrieder W, Rapp H, Rau F, Renner H, Riedler H, Ringler H, Sardei F, Schüller PG, Schwörer K, Siller G, Söldner F, Steuer K, Thumm M, Tutter M, Vollmer O. Experimental study of the principles governing tokamak transport. Phys Rev Lett 1986; 56:2187-2190. [PMID: 10032913 DOI: 10.1103/physrevlett.56.2187] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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50
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Aritake K, Mayer HM, Fritschka E, Cervós-Navarro J, Takakura K. [Cerebral hemodynamics in chronic hypoxic hypoxia]. No To Shinkei 1986; 38:363-9. [PMID: 3718781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The effects of chronic-hypoxic hypoxia on cerebral blood flow and its regulating mechanisms were investigated by means of intracardiac injection of radioactively labelled microspheres. In a gas chamber designed and constructed for the purpose, adult cats were exposed to stepwise decreasing inspiratory oxygen concentrations (for 4.5 months with a final O2 concentration of 8 vol%). Using animals adapted to hypoxic hypoxia, responsiveness of cerebral blood flow either to alterations in systemic arterial pressure (SAP) or to alterations in arterial blood oxygen tension (PaO2) were assessed. Flow measurement was done under three different conditions: normoxic normotension (PaO2 greater than 100 mmHg; SAP greater than 100 mmHg), hypoxic normotension (PaO2 = 30 mmHg; SAP greater than 100 mmHg), or normoxic hypotension (PaO2 greater than 100 mmHg; SAP = 60 mmHg). Hematocrit values continuously increased to 56% during the process of adaptation to hypoxia. There was also a remarkable increase in cardiac output of hypoxia-adapted animals subjected to hypoxia and to normoxia. Chronic-hypoxic hypoxia led to increased cerebral blood flow, which persisted even when animals were returned to normoxia. Under hemorrhagic hypotension, cerebral blood flow fell significantly in animals adapted to chronic-hypoxic hypoxia but did not fall short of the absolute values in controls. The relative reduction in cerebral blood flow might be attributable to the decrease in cardiac output and to altered blood viscosity. This implied that, even in animals subjected to long-standing graded hypoxic hypoxia, autoregulatory capacity might be partly preserved.
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