F. Popken

Iatrogenic paraplegia in spinal surgery

IntroductionParaplegia as a result of a surgical spinal procedure is a rare complication. The risk cannot be precisely quantified due to the lack of current data. The aim of this study was to record a sufficiently large number of major spinal operations, especially extended methods in scoliosis surgery. Hereby, a reliable statement regarding the risk of severe neurological complications with these surgical techniques should be possible. First, a retrospective analysis of patients from a German spine centre (spinal fusion) and a survey of 17 German centres of spinal surgery were conducted for the retrospective acquisition of severe iatrogenic neurological complications.Materials and methodsThe study included 1194 patients who underwent a spinal fusion during the period 1992–2002. The incidents of postoperative paraplegia are described in detail, and case studies done. Possible causes, methods of intraoperative monitoring and options of therapy are discussed according to research in relevant publications. Additionally, severe neurological complications of 3115 spinal operations were recorded in a standardised survey conducted throughout major German spinal centres.ResultsOf the 1194 patients surveyed, 7 (0.59%) experienced a postsurgical complete or incomplete paraplegia. In 3 of the recorded cases, the cause could be identified. The survey of 3115 scoliosis surgeries showed that iatrogenic paraplegia occurred with a frequency of 0.55%. The risks associated with short spinal fusions (0.14%), cervical discectomies (0.07%) and lumbar discectomies (0.03%) are considerably less.ConclusionOperative treatment of scoliosis with a high degree of correction carries a risk of neurological complications of about 0.5%. Mechanical as well as ischaemic damage to the spinal cord can be detected early by means of consistent intraoperative neuromonitoring.

Intraosseous lipoma of the calcaneus.

Abstract. Background and aims: Intraosseous lipoma of the calcaneus is thought to be a rare tumour. As most of the articles have been single case reports, we performed a meta-analysis to evaluate diagnostic and therapeutic procedures. Methods: Based on 54 cases located at the calcaneus, typical features and treatment were studied. Results: A predilection was seen for adults between 30 and 60 years of age. Males were affected in two of three cases. The lesions were found incidentally in 33%. Symptomatic cases presented with pain, and some patients showed additional tenderness or swelling. All calcaneal lipomas were located at the base of the neck of the calcaneus (Wards triangle). Radiological appearance depends on the stage due to evolutionary changes of the tumour. Diagnosis can be established with CT or MRI, as both methods show fat-equivalent densities in the lesion. Pathological fracture has not been reported. Conclusion: Continued observation in asymptomatic cases is a reasonable clinical approach. We propose surgical treatment with curettage and bone grafting only in symptomatic cases.

Cryosurgery in long bones with new miniature cryoprobe: an experimental In vivo study of the cryosurgical temperature field in sheep

AIM The aim of this in vivo study was to determine whether new miniature cryoprobes provide adequate tissue cooling in long bones by measuring the field of temperature under various conditions. METHODS Freezings were performed in femoral and tibial bones of 10 sheep under general anaesthesia. Applying one cryoprobe, temperatures of -75 degrees C resp. -51 degrees C could be reached within 0.75 cm resp. 1.00 cm of the probe. RESULTS Histological examinations revealed compact bone and marrow necroses along the isotherm in all 10 sheep. Using two cryoprobes simultaneously, a mean temperature decrease to -71 degrees C between the two cryoprobes was achieved thanks to the synergistic freezing effect. Looking at consecutive freezes, it was apparent that with similar cryoprobe end temperatures, the temperature dropped faster if the number of freezing cycles was increased. CONCLUSION In conclusion, it was seen that despite its small diameter, the new miniature cryoprobe delivers adequate in vivo tissue cooling in long tubular bones. Employing the synergistic freezing effect by using two or more cryoprobes simultaneously, efficient in vivo freezing of larger bone segments is also possible. Thus, cryosurgery with the new miniature probes can provide a valuable complement to conventional resection of long tubular bones, and offers a viable alternative to surgical treatment of neoplastic diseases of the skeletal system.

Behandlungsergebnisse nach operativer Versorgung ossärer Mammakarzinommetastasen Prophylaktische Stabilisierung vs. Versorgung nach pathologischer Fraktur

ZusammenfassungFragestellung, Methodik. Den Vorteilen der prophylaktischen Versorgung von frakturgefährdeten, ossären Metastasen des Mammakarzinoms stehen das perioperative Risiko sowie konservative Alternativen gegenüber. Da bei konservativem Vorgehen im Einzelfall eine pathologische Fraktur nicht sicher ausgeschlossen werden kann, wurden in einer retrospektiven Studie die Behandlungsergebnisse nach pathologischer Fraktur (n=35) mit denen nach prophylaktischer Versorgung (n=44) verglichen. Ergebnisse. Bei insgesamt 20,3% (n=16) intraoperativen, kardiopulmonalen Komplikationen waren diese in beiden Gruppen gleichverteilt. Intraoperative, operationstechnische Komplikationen (n=3) traten ausschließlich in der Frakturgruppe auf. Allgemeine, postoperative Komplikationen sahen wir in 20,3% (n=16) aller Fälle, wobei die Patientinnen der Frakturgruppe mit 28,6% (n=11/35) vs. 11,4% (n=5/44, Prophylaxegruppe) vermehrt betroffen waren (p<0,02). Während sich bei den postoperativen operationstechnischen Komplikationsraten keine Unterschiede zwischen beiden Gruppen zeigten, erreichten in der Prophylaxegruppe mit 91,9% (n=40/44) vs. 74,3% (n=26/35) in der Frakturgruppe signifikant mehr Patientinnen die volle postoperative Gebrauchsfähigkeit der operierten Region (p<0,05). Die durchschnittliche Überlebenszeit war in der Prophylaxegruppe tendenziell länger [19,3±15,6 Monate (Prophylaxegruppe) vs. 15,0±16,9 Monate (Frakturgruppe)]. Schlussfolgerungen. Die prophylaktische Versorgung bei frakturgefährdeten, ossären Metastasen des Mammakarzinoms bedeutet also im Vergleich zu den Patientinnen mit pathologischer Fraktur insgesamt eine Verringerung der postoperativen, allgemeinen Komplikationsrate und zudem eine höhere Chance der einzelnen Patientin, postoperativ die volle Mobilität wiederzuerlangen. Angesichts langer Überlebenszeiten nach Auftreten ossärer Metastasen beim Mammakarzinom stellt somit die prophlaktische Versorgung bei drohender Fraktur die Methode der Wahl gegenüber dem konservativem Vorgehen mit persistierendem Frakturrisiko dar.AbstractAim of the study, method. The advantages of a prophylactic care of fracture-endangered, osseous metastasis of the mammary cancer stand opposite to the perioperative risk and to conservative alternatives. As a pathologic fracture cannot surely be excluded while performing a conservative proceeding, a retrospective trial was set up to compare the results of treatment after a pathologic fracture (n=35) with those undergoing a prophylactic attendance (n=44). Results. The intraoperative, cardio-pulmonary complications were distributed in balance totally amounting to 20,3% (n=16). Intraoperative complications concerning surgical procedure (n=3) exclusively occurred within the fracture group. Generally, postoperative complications arose in 20,3% (n=16) of all cases, in which the patients belonging to the fracture group were increasingly afflicted [28,6% (n=11/35) vs. 11,4% (n=5/44); p<0,02]. While there were no differences between both groups concerning the postoperative, surgery-technical complications, significantly more patients (91,8% [n=40/44]) of the prophylactic-care group achieved a complete postoperative usability of the operated area than in the fracture-group [74,3% (n=26/35)] (p<0,05). The average survival time tended to be longer within the prophylactic-care group [19,3±15,6 month (prophylactic-care group) vs. 15,0±16,9 month (fracture group)]. Conclusions. The prophylactic treatment of fracture endangered, osseous metastasis of the mammary cancer leads to reduction of the general, postoperative complications compared to the patients with a pathologic fracture. Further, those patients have a better chance to recover full mobility after surgery. Considering the long survival time after the incidence of osseous metastasis at the mammary cancer a prophylactic treatment represents the method of first choice compared with the conservative treatment which persistently contains the risk of fracturing.

The use of a new miniature cryoprobe for ablation of bone tissue: In vivo assessment of the probe and application of the method to bone in a sheep model

BackgroundSo far, modern miniature cryoprobes were used for local destruction of soft tissue tumours without damaging the adjacent healthy tissue. In this study, cryoablation methodology was applied to bone and the cooling capacity of the probe was examined in vitro and in vivo.MethodFreezing was performed by cooling one or two probes (diameter 3.2 mm) to -180°C with liquid nitrogen. The cooling capacity of the probes was determined optically and thermally against a homogeneous reference gel, followed by in vivo measurements on femoral and tibial sheep bone followed by histological examination.ResultsThanks to the synergistic effect, the simultaneous use of 2 probes produced an almost spherical expansion of cold in the homogenous gelatin. During the in vivo freezes, the temperature curves showed a more moderate trend. Nevertheless, due to the synergistic effect, temperatures below -50°C could be reached at a distance of 1 cm from the probe. No local or systemic intraoperative complications were observed. Histological examination revealed cell necrosis up into the -10°C isotherm.ConclusionsAdequate tissue cooling of the bone matrix can be achieved with in vivo freezes by means of one or more miniature cryoprobes. Therefore, this probe could provide an alternative to or supplement surgical resection of pathological bone processes.

[The minimally invasive unicompartmental knee system "Preservation"First clinical results and analysis of complications].

ZusammenfassungMit dem „Preservation Knie“ steht ein System zur Verfügung, das es ermöglicht, minimal-invasiv mit knochensparender Resektion eine unikompartimentelle Knieendoprothese zu implantieren. Die zurzeit vorliegenden Frühergebnisse zeigen, dass diese Operationstechnik eine schnellere Mobilisation der Patienten ermöglicht. Das Mobile-bearing-Inlay hat biomechanische Vorteile, ist jedoch schwieriger zu implantieren, und die Komplikationsrate ist anfänglich höher. Die darum erforderliche chirurgische Sorgfalt ist für die Mobile-bearing-Variante einerseits mit einer längeren Lernkurve und andererseits mit einer geringeren Fehlertoleranz als für die anderen Varianten verbunden.Die Verwendung des jetzt vorhandenen Navigationsmoduls kann die Implantationsgenauigkeit erhöhen. Dieses neue Implantat muss sich jedoch im Verlauf erst noch mit den guten Langzeitergebnissen anderer unikompartimenteller Prothesen vergleichen.AbstractThe Preservation uni knee system is a minimally invasive procedure for implantation of a unicompartmental knee prosthesis. The early results show that the rehabilitation process is quick; the postoperative pain and blood loss is less than after conventional knee arthroplasty. Still there are some pitfalls. The implantation of the tibial mobile-bearing component requires a sound operative technique; otherwise complications will occur. The combination of the available navigation system with the Preservation uni will improve operative accuracy.The Preservation uni knee system is a minimally invasive procedure for implantation of a unicompartmental knee prosthesis. The early results show that the rehabilitation process is quick; the postoperative pain and blood loss is less than after conventional knee arthroplasty. Still there are some pitfalls. The implantation of the tibial mobile-bearing component requires a sound operative technique; otherwise complications will occur. The combination of the available navigation system with the Preservation uni will improve operative accuracy.

Der minimal-invasive Halbschlitten „Preservation“

ZusammenfassungMit dem „Preservation Knie“ steht ein System zur Verfügung, das es ermöglicht, minimal-invasiv mit knochensparender Resektion eine unikompartimentelle Knieendoprothese zu implantieren. Die zurzeit vorliegenden Frühergebnisse zeigen, dass diese Operationstechnik eine schnellere Mobilisation der Patienten ermöglicht. Das Mobile-bearing-Inlay hat biomechanische Vorteile, ist jedoch schwieriger zu implantieren, und die Komplikationsrate ist anfänglich höher. Die darum erforderliche chirurgische Sorgfalt ist für die Mobile-bearing-Variante einerseits mit einer längeren Lernkurve und andererseits mit einer geringeren Fehlertoleranz als für die anderen Varianten verbunden.Die Verwendung des jetzt vorhandenen Navigationsmoduls kann die Implantationsgenauigkeit erhöhen. Dieses neue Implantat muss sich jedoch im Verlauf erst noch mit den guten Langzeitergebnissen anderer unikompartimenteller Prothesen vergleichen.AbstractThe Preservation uni knee system is a minimally invasive procedure for implantation of a unicompartmental knee prosthesis. The early results show that the rehabilitation process is quick; the postoperative pain and blood loss is less than after conventional knee arthroplasty. Still there are some pitfalls. The implantation of the tibial mobile-bearing component requires a sound operative technique; otherwise complications will occur. The combination of the available navigation system with the Preservation uni will improve operative accuracy.The Preservation uni knee system is a minimally invasive procedure for implantation of a unicompartmental knee prosthesis. The early results show that the rehabilitation process is quick; the postoperative pain and blood loss is less than after conventional knee arthroplasty. Still there are some pitfalls. The implantation of the tibial mobile-bearing component requires a sound operative technique; otherwise complications will occur. The combination of the available navigation system with the Preservation uni will improve operative accuracy.

Complications after cryosurgery with new miniature cryoprobes in long hollow bones: An animal trial

BackgroundIn vitro studies show that new miniature cryoprobes are suitable for cryoablation of bone tissue. The aim of this animal trial on 24 sheep was to examine the perioperative complications, particularly the danger of embolism, of cryoablation when using miniature cryoprobes.MethodsCryoablations with 2 freeze-thaw cycles each were carried out in the epiphysis of the right tibia and the metaphysis of the left femur. Pulmonary artery pressure (PAP) and central venous pressure (CVP) were measured. Throughout the intra- and perioperative phase, heart rate and oxygen saturation by pulse oxymetry, blood gas and electrolytes were monitored regularly. Postoperative complications were examined up to 24 weeks postoperativ.ResultsAs result, no significant increase of PAP, CVP or heart rate were observed. Blood gases were unremarkable, with pO2 and pCO2 remaining constant throughout the operation. Regarding pH, standard bicarbonate and base excess, only a non-significant shift towards a slight acidosis was seen. There was a mean hemoglobin decrease of 0.5 g/dl. One animal showed postoperative wound infection and wound edge necrosis. No major peri- and postoperative complications associated with cryosurgery of bone were observed, especially regarding clinically relevant pulmonary embolism.ConclusionSurgery with new types of miniature cryoprobes appears to be a safe alternative to or a complement to conventional resection of abnormal bone tissue.

Muskelfunktionsgrundlagen aus orthopädischer Sicht

ZusammenfassungDer orthopädische Untersuchungsgang beinhaltet neben der klinischen Untersuchung auch die Kenntnis der Muskelzusammensetzung, der Stufen der Muskelkraft und mögliche Auswirkungen über Formen der Muskelverkürzung. Im Rahmen der Muskelfunktionstests können Aussagen über die Kraft einzelner Muskeln oder Muskelgruppen, die eine funktionelle Einheit bilden, gemacht werden.AbstractAs well as the clinical examination, an orthopaedic investigation must be based on knowledge of the muscular structure, the grading system for muscular force, and the possible effects of the various forms of muscular contraction. Muscle function tests can yield information about the muscular strength of separate muscles or of groups of muscles that make up functional units.