[Revolution in spinal surgery. What is the value of intervertebral disk prostheses? (interview by Waldtraut Paukstadt)].
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Humans↗
Biomedical subjects
H M Mayer
Publications and source records attributed to H M Mayer.
[Discogenic low back pain and degenerative lumbar spinal stenosis - how appropriate is surgical treatment?].
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.
Diagnosis, Differential↗
The ALIF concept.
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.
Adolescent↗
Spinal epidural abscess following blunt pelvic trauma.
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.
Accidental Falls↗
Influence of muscle forces on loads in internal spinal fixation devices.
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.
Abdominal Muscles↗
Placing a bone graft more posteriorly may reduce the risk of pedicle screw breakage: analysis of an unexpected case of pedicle screw breakage.
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.
Activities of Daily Living↗
A new microsurgical technique for minimally invasive anterior lumbar interbody fusion.
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.
Adult↗
[SICOT '95. Current developments in spinal surgery. Amsterdam 8-18-23, 1996].
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Humans↗
Endoscopic discectomy in pediatric and juvenile lumbar disc herniations.
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.
Adolescent↗
Clamping stiffness and its influence on load distribution between paired internal spinal fixation devices.
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.
Humans↗
Telemeterized load measurement using instrumented spinal internal fixators in a patient with degenerative instability.
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.
Bone Screws↗
The "mirror image" and "two-thirds" types of hemispherical spondylosclerosis.
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)
Adult↗
Exogenous lumbar spondylodiscitis following a stabwound injury and vertebral fracture. A case report and review of the literature.
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.
Adult↗
[Spondylitis: borderline findings in magnetic resonance tomography].
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.
Adult↗
[Technique and economics of first worldwide roentgen conference via public phone lines with the Medical Desktop-Conference and Integrated Services Digital Network].
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.
Computer Communication Networks↗
Spine update. Percutaneous lumbar disc surgery.
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.
Diskectomy, Percutaneous↗
[MRT in degenerative diseases of the cervical spine].
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.
Cervical Vertebrae↗