[Minimally invasive decompression techniques for spinal cord stenosis]. / Minimal-invasive Dekompressionsverfahren der Spinalkanalstenose.

BACKGROUND: Lumbar spinal canal stenosis is frequently found among elderly patients and significantly limits their quality of life. Non-surgical therapy is an initial treatment option; however, it does not eliminate the underlying pathology. Surgical decompression of the spinal canal has now become the treatment of choice. OBJECTIVE: Minimalization of surgical approach strategies with maintaining sufficient decompression of the spinal canal and avoiding disadvantages of macrosurgical techniques, monolateral paravertebral approach with bilateral intraspinal decompression, specific surgical techniques. MATERIALS AND METHODS: Minimally invasive decompression techniques using a microscope or an endoscope are presented and different surgical strategies depending on both the extent (mono-, bi-, and multisegmental) and the location of the stenosis (intraspinal central, lateral recess, foraminal) are described. RESULTS: Minimally invasive microscopic or endoscopic decompression procedures enable sufficient widening of the spinal canal. Disadvantages of macrosurgical procedures (e. g., postoperative instability) can be avoided. The complication spectrum overlaps partially with that of macrosurgical interventions, albeit with significantly less marked severity. Subjective patient outcome is clearly improved. CONCLUSIONS: Referring to modern minimally invasive decompression procedures, surgery of lumbar spinal canal stenosis represents a rational and logical treatment alternative, since causal treatment of the pathology is only possible with surgery.

[Microsurgery of acquired degenerative lumbar spinal stenosis. Bilateral over-the-top decompression through unilateral approach]. / Mikrochirurgie bei degenerativer lumbaler Spinalstenose. Bilaterale Over-the-top-Dekompression durch unilateralen Zugang.

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.

A memory coiling spiral as nucleus pulposus prosthesis: concept, specifications, bench testing, and first clinical results.

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.

Minimally invasive total disc replacement: surgical technique and preliminary clinical results.

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.

A spiral implant as nucleus prosthesis in the lumbar spine.

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.

Strategy for the treatment of patients with spinal neoplasms.

Progress in oncological therapy within the last decade has enhanced the survival time of patients suffering from tumorous osteolyses of the spine. While the necessity of surgical intervention is often settled by acute clinical symptoms, the extent of surgery is certainly co-determined by the patient's expectations and the time of survival to be expected. We therefore developed a specific tumor algorithm for operations on the spine with special emphasis on prognosis and the attainable quality of life. The results of 154 patients with tumorous osteolyses of the thoracic and lumbar spine, who were treated according to our algorithm, underline the unequivocal advantages of initially posterior procedures.

[Use of ultrasonography in the diagnosis of infections in the locomotor apparatus--possibilities and limitations]. / Einsatz der Sonografie zur Infektdiagnostik am Stütz- und Bewegungsapparat--Möglichkeiten und Grenzen.

Significance of sonography in the detection of soft tissue infections is unclear and discussed controversial in literature. In a retrospective study sonograms of 40 hematomas and 23 infections were evaluated to examine the possibility of detecting infections by means of sonography alone. Accumulation of fluid, however, could not be differentiated by the established sonomorphological criteria. Especially in postoperative infections with unclear clinical pattern no differentiation between hematoma and abscess could be made. Only ultrasonically guided transcutaneous needle aspiration biopsy can prove the character of sonographic findings.

The importance of sonography in the diagnosis of septic complications following spinal surgery.

The detection of infection after surgery on the thoracic and lumbar spine is difficult due to the anatomical circumstances. Clinical symptoms, laboratory findings, and most radiological techniques are of limited diagnostic value. Among other benefits, sonography offers the advantage of early postoperative examination, even with metal implants in the operated area. In a retrospective study, 27 patients with clinically suspicious wounds were evaluated by sonography in the postoperative follow-up; all cases were verified by puncture and/or operative revision. Eleven cases turned out to be hematomas, and 16 cases were found to be infections. Accumulations of fluid, however, could not be differentiated by the established sonomorphological criteria such as internal echo structures, septation, demarcation from the environment, and reaction of the surrounding tissue. Ultrasonically guided transcutaneous needle aspiration biopsy served to differentiate the local findings and to establish the diagnosis and therefore is required as an obligatory method of investigation.

Influence of edge sharpness on the accommodation of the human eye.

Using a subjective method of laser refractometry, the accommodation behavior of six subjects toward real targets with various degrees of blur, dependent on the viewing distance, were investigated monocularly and binocularly. Despite the sharpness of the target, the nominal value is only reached incompletely with a lag of accommodation, because accommodation tends to be as minimal as possible. Increasing blurring leads to a drift of accommodation towards the resting position of accommodation. The resulting underaccommodation causes further physiological blurring of the retinal image of the targets. The approach of the targets to the resting position of accommodation leads to a higher precision of adjustment and less drift. Subjective components (accommodative laziness, cognitive demand) influence the accommodation and increase the phenomenons discovered.