Jürgen Sterk

FUNCTIONAL EVALUATION OF THE 10-YEAR OUTCOME AFTER MODIFIED EVANS REPAIR FOR CHRONIC ANKLE INSTABILITY

The Evans tenodesis is an operative treatment for chronic ankle instability with good short-term results. 18,24,25 The disadvantage of impaired hind foot kinematics and restricted motion has been described, 6,16 and only few reports of long-term results can be found. 14 No techniques have been used to assess the outcome objectively. We wanted to determine whether a modified Evans procedure 33 led to a satisfactory clinical and functional outcome. Nineteen patients were available at a 10-year follow-up. The clinical examination included a detailed questionnaire and stress radiographs. Foot function was evaluated with plantar pressure distribution measurements during walking and peroneal reaction time measurements elicited on a rapidly tilting platform (recorded with surface electromyography). High subjective patient satisfaction was contrasted with a high rate of residual instability, pain, and swelling. The radiographs showed an increased number of exostoses. The gait analysis revealed reduced peak pressures under the lateral heel and increased values under the longitudinal arch. The reaction times of the peroneal muscles were shorter on the operated side (significant: peroneus longus). The persistent clinical problems as well as the functional changes indicate that the disturbed ankle joint kinematics permanently alter foot function and may subsequently support the development of arthrosis. Therefore, the Evans procedure should only be applied if anatomical reconstruction of the lateral ankle ligaments is not feasible.

Measurement of intracompartmental pressure with use of a new electronic transducer-tipped catheter system

Laboratory and clinical tests were carried out to determine the clinical usefulness, validity, and safety of a new self-calibrating, battery-powered monitoring system for the measurement of intramuscular pressure with use of an electronic transducer-tipped catheter. The eight probes accurately recorded applied pressures ranging from zero to 160 millimeters of mercury (zero to 21.33 kilopascals). The system registered little temperature-induced drift (maximum, 1.25 millimeters of mercury [0.17 kilopascal]) between dry room temperature and 40 degrees Celsius. There were also minimum variations (range, -0.14 to 0.81 millimeter of mercury [0.02 to 0.11 kilopascal]) in the pressures recorded during a twenty-four-hour period. The resting pressure in the tibialis anterior muscle of twenty volunteers who had normal limbs was a mean (and standard deviation) of 13.1+/-8.3 millimeters of mercury (1.75+/-1.11 kilopascals). There was a good correlation between externally applied pressures (zero, twenty, forty, sixty, eighty, and 100 millimeters of mercury [zero, 2.67, 5.33, 8.00, 10.66, and 13.33 kilopascals] applied with use of antishock trousers) and the pressures measured in the tibialis anterior muscle of four volunteers (r = 0.997 to 0.999). The injection of sterile saline solution into the tibialis anterior muscle of a volunteer and the use of high-frequency recording during muscular activity showed a high degree of responsiveness and sensitivity to changes in intramuscular pressure. We also prospectively evaluated the clinical usefulness of the system and found it to be easy to assemble, calibrate, and use. Thus, this reusable, electronic transducer-tipped catheter system, which is based on a noninfusion technique, is simple, minimally traumatic, and highly precise. It is free of hydrostatic pressure artifacts and provides dynamic responses to changes in intramuscular pressure.

Intrakompartimentelle Druckmessung beim akuten Kompartmentsyndrom Ergebnisse einer Umfrage zu Indikation, Messtechnik und kritischem Druckwert

ZusammenfassungDer Stellenwert der intrakompartimentellen Gewebedruckmessung bei Verdacht auf ein akutes Kompartmentsyndrom und der kritische Grenzwert, ab dem die Fasziotomie indiziert ist, wird kontrovers diskutiert. Daher sollte das diagnostische Management beim akuten Kompartmentsyndrom im deutschsprachigen Raum untersucht werden. Hierfür wurde eine Umfrage im Rahmen der Jahrestagung der Deutschen Gesellschaft für Unfallchirurgie im November 1997 durchgeführt. 420 Fragebögen konnten ausgewertet werden.Bei klinischem Verdacht auf ein akutes Kompartmentsyndrom führten 50,9% der Befragten (n=214) Kompartmentdruckmessungen durch. Dabei lag der Anteil derer, die zwar bei klinischem Verdacht Gewebedruckmessungen durchführten, den Ergebnissen jedoch nur einen geringen bis mäßigen Stellenwert zuordneten mit 43,7% (n=90) erstaunlich hoch. Im Gesamtkollektiv ordneten 61,8% (n=215) der Gewebedruckmessung einen geringen bis mäßigen Stellenwert zu.Bei den Messystemen kamen in der Mehrheit die Geräte Stryker® (63,1%, n=135) und Coach® (12,1%, n=26) zum Einsatz. Über die klinische Untersuchung und ggf. die Gewebedruckmessung hinaus setzten 175 (41,7%) der Befragten zusätzliche apparative Diagnostika ein. Die Indikation zur Fasziotomie wird von 110 (51.4%) der Messenden anhand eines fixen Druckwertes gestellt. Demgegenüber fließen bei 104 Chirurgen (48,6%) hämodynamische Parameter in die Entscheidung zur Fasziotomie mit ein.In der Gesamtsicht zeigte sich bei den Befragten im Hinblick auf das diagnostische Management beim akuten Kompartmentsyndrom eine extrem uneinheitliche Vorgehensweise. Die eingesetzten Messmethoden und der angegebene kritische Logendruck stimmte nur selten mit den gängigen Literaturempfehlungen überein.AbstractThe early diagnosis of acute compartment syndrome is very important, compartment monitoring is advocated. There is however still some controversy regarding the use of compartment pressure measurement devices in the diagnosis of acute compartment syndrome. We present the results of a survey that was designed to explore this issue in Germany.In the case of suspected acute compartment syndrome 50.9% (n=214) of the surgeons perform intracompartmental pressure measurement. Pressure measurement is of lower significance for 61.8% (n=215) surgeons questioned. Additional apparative diagnostics is performed by 41.7% of the surgeons. A large majority apply the Stryker® device (63.1%, n=135), followed by the Coach® device (12.1%, n=26). The pressure threshold for intervention is recommended by 51.4% (n=110) of the traumatologists as an absolute compartment pressure value. The remaining 48.6% (n=104) include haemodynamic parameters in their decision.The surgeons employ widely differing methods of approach in the diagnosis of acute compartment syndrome. Some of these are extremely different from the methods recommended in the literature.

Das akute Kompartmentsyndrom Ergebnisse einer klinisch-experimentellen Studie zu Druck- und Zeitgrenzwerten für die Notfallfasziotomie

ZusammenfassungProblemstellung: Das akute Kompartmentsyndrom der Extremitäten ist eine unfallchirurgische Notfallsituation. Einigkeit besteht darüber, dass nur eine frühzeitige operative Dekompression der betroffenen Muskelloge schwerwiegende Folgeschäden verhindern kann. Kontrovers wird jedoch der kritische Muskelgewebedruck diskutiert, ab dem ein derartiger Eingriff erfolgen soll. Humanstudien, die gleichzeitig den Gewebedruck und die Muskeloxygenation untersuchten, liegen bisher nicht vor. Daher sollte in einer Kompartmentsyndrom-Modellsituation der Gewebe-O2-Partialdruck und das Summenaktionspotential des N. peronaeus profundus analysiert werden. Methodik: Bei 22 normotensiven gesunden Freiwilligen wurden mit dem Beinsegment einer Antischockhose im M. tibialis anterior Druckwerte zwischen 0 und 100 mmHg erzeugt. Über einen Zeitraum von bis zu 6 h erfolgte die Messung des Gewebedrucks, der O2-Spannung (pO2) im M. tibialis anterior und elektromyographisch die Ableitung des Muskelsummenaktionspotenzials des N. peronaeus profundus. Ergebnisse:Übertragung des pneumatischen Drucks zu 97,7% (Q25%/Q75%: 89,2/99,8) auf den Extremitätenmuskel. Bereits bei niedrigen intramuskulären Druckwerten (30–40 mmHg) traten eine Hypoxie und Einschränkung des Muskelsummenaktionspotentials (MASP) auf. Eine Reduktion des MSAP auf Null und ein pO2 <1 mmHg war ab einem Druck von 50 mmHg zu beobachten. Gewebedruckwerte von über 75 mmHg resultierten nahezu ausnahmslos in einer Anoxie des Muskels. Schlussfolgerung: Selbst unter optimalen Perfusionsbedingungen führen bereits geringe Druckerhöhungen auf über 30 mmHg zur verminderten Gewebeoxygenation und Einschränkung der neuralen Funktion. Berücksichtigt werden muss, dass bei zusätzlich traumatisiertem Muskel die Ischämietoleranz des Gewebes erheblich vermindert und infolge zahlreicher, unbestimmbarer Einflussfaktoren (lokale Gefäßreaktivität, Autoregulation, Zentralisation) die lokale nutritive Perfusionssituation nicht sicher beurteilbar ist. Beim Patienten mit schwerem Weichteiltrauma sollte daher der aus Sicherheitsgründen niedrig gewählte absolute Druckwert von 30 mmHg als Grenze gelten.AbstractBackground: Acute compartment syndrome of the leg is to be regarded as a traumatological emergency. Most specialists already agree that only a timely operative decompression of the afflicted compartment can prevent serious tissue damage. What still remains subject to discussion, however, is the precise tissue pressure above which the operation becomes imperative. Experimental human studies focusingon tissue pressure and muscle oxygenation have not yet been carried out. It was thus the aim of the present study to analyze oxygen partial pressure of the anterior tibial muscle and peroneal action potential in a model compartment syndrome in man. Methods: In 22 healthy, normotensive volunteers, constant pressure values from 0 to 100 mmHg were induced in the anterior tibial muscle with antishock trousers. Over a period of up to 6 h measurements were made of (1) tissue pressure, (2) intramuscular oxygen partial pressure (pO2), and (3) muscle response potential (MRP) of the n. peroneus profundus by electroneurography. Results: We achieved a 97.7% (Q25%/Q75%: 89.2/99.8) transfer of the pneumatic pressure to the lower leg. Already at intramuscular tissue pressures of 30–40 mmHg, hypoxia and reduction of MRP appeared. A reduction of the MRP to zero and pO2 <1 mmHg was observed from a pressure of 50 mmHg. Tissue pressure values of over 75 mmHg resulted almost without exception in anoxia of the muscle. Conclusions: Even under normal perfusion conditions, already slight increases in pressure of above 30 mmHg lead to reduced tissue oxygenation and neural function. We have to consider that with additionally traumatized muscle the ischemic tolerance is markedly reduced and due to unknown influences such as local vasoreactivity and capacity of autoregulation the nutritive perfusion cannot be determined. In the case of a severely injured muscle, to be on the safe side decompressive fasciotomy should therefore be carried out if pressure values remain above 30 mmHg.

LONG-TERM RESULTS OF THE MODIFIED EVANS REPAIR FOR CHRONIC ANKLE INSTABILITY

We treated 19 patients for chronic ankle instability with a modified Evans procedure. All patients were evaluated after an average follow up of 128 months with detailed questionnaire, clinical examination, and stress radiographs. Although the subjective results were reported as 8 excellent, 7 good, and 4 fair, residual pain was reported by 11 patients. There was a significantly increased number of osteophytes in the treated ankle joint. Stress radiographs demonstrated significantly improved stability in the operated ankle joint. Range of motion was significantly reduced in hindfoot inversion. The results showed that the modified Evans procedure achieved sufficient joint stability at the expense of inversion range of motion. This reconstruction method apparently did not prevent the development of arthrosis.

Intramuscular pressure, tissue oxygenation and EMG fatigue measured during isometric fatigue-inducing contraction of the multifidus muscle

Simultaneous measurement of intramuscular pressure (IMP), tissue oxygen partial pressure (pO2) and EMG fatigue parameters in the multifidus muscle during a fatigue-inducing sustained muscular contraction. The study investigated the following hypotheses: (1) Increases in IMP result in tissue hypoxia; (2) Tissue hypoxia is responsible for loss of function in the musculature. The nutrient supply to muscle during muscle contraction is still not fully understood. It is assumed that muscle contraction causes increased tissue pressure resulting in compromised perfusion and tissue hypoxia. This tissue hypoxia, in turn, leads to muscle fatigue and therefore to loss of function. To the authors’ knowledge, no study has addressed IMP, pO2 and EMG fatigue parameters in the same muscle to gain a deeper sight into muscle perfusion during contraction. As back muscles need to have a constant muscular tension to maintain trunk stability during stance and locomotion, muscle fatigue due to prolonged contraction-induced hypoxia could be an explanation for low back pain. Sixteen healthy subjects performed an isometric muscular contraction exercise at 60% of maximum force until the point of localized muscular fatigue. During this exercise, the individual changes of IMP, pO2 and the median frequency (MF) of the surface EMG signal of the multifidus muscle were recorded simultaneously. In 12 subjects with a documented increase in intramuscular pressure, only five showed a decrease in tissue oxygen partial pressure, while this parameter remained unchanged in six other subjects and even increased in one. A fall in tissue pO2 was associated with a drop in MF in only five subjects, while there was no correlation between these parameters in the other 11 subjects. To summarize, an increase in IMP correlated with a decrease in pO2 and a drop in MF in only five out of 16 subjects. High intramuscular pressure values are not always associated with a hypoxia in muscle tissue. Tissue hypoxia is not automatically associated with a median frequency shift in the EMG signal’s power spectrum.

Drainage systems in thyroid surgery: a randomised trial of passive and suction drainage.

OBJECTIVE To investigate the effectiveness of high-vacuum and passive drainage systems after elective thyroid resection. DESIGN Prospective randomised clinical study and multicentre postal survey. SETTING Military hospital, Germany. PATIENTS 80 patients, treated with passive closed drains (n = 40) or high-vacuum systems (n = 40). INTERVENTIONS 1. Measuring the amount of blood collected during drainage and the extent of residual haematoma on ultrasonography. 2. Survey in Austria, Germany and Switzerland of annual number of bilateral thyroid resections, type of drainage used, and volume of postoperative drainage. RESULTS 799 of the 1698 hospitals surveyed replied (47.2%). 785 (98.2%) of the 799 surgeons said that they used drainage systems of whom 766 (97.6%) used high-vacuum systems. In the 40 patients in whom passive closed drainage was used, the median volume drained was 34 ml (range 0-175) compared with 115 ml (40-346) in the high vacuum group (p < 0.01). In the passive drainage group the extent of residual haematoma measured by us was 4.4 ml (range 0-21.7) compared with 5.3 ml (0.6-24.9) in the high vacuum group. CONCLUSIONS The high-vacuum drainage that is most commonly used in Austria, Germany, and Switzerland results in increased blood loss with no reduction in the extent of residual wound haematoma and offers no additional advantage over passive drainage systems in thyroid surgery.

The significance of intracompartmental pressures in diagnosing chronic exertional compartment syndrome – A metaanalysis of studies monitoring dynamic anterior compartment pressures during exercise

SummaryIntroduction: The chronic exertional compartment syndrome of the musculus tibialis anterior is thought to be responsible for a major part of complaints of the lower leg among active sportsmen. There is an important role of tissue pressure measurement in diagnosing chronic anterior compartment syndrome during muscular activity. However, there is a controversial debate about the relevant parameters. Methods: Metaanalysis of all the 21 studies (1979–1998) measuring intracompartmental pressures during muscular activity. Parameters of analysis: type of exercise, catheter technique, recommendations of diagnostic criteria. Results: Analysis of literature shows that there has been no standardisation concerning the type of muscular exertion (isometrics for 5–10 min, exercise on the treadmill between 3.2 and 12 km/h). In 8 of the 21 studies the results have been attained through the unsuitable Wick-catheter-technique. In the overall view none of the suggested criterions for diagnosis is taken up by other teams. There are considerable variations up to 500 % regarding the recommended parameters. Conclusions: From all studies no uniform recommendation for parameters of diagnostic relevance can be derived. On this background it should be demanded that future research is conducted by a uniform regimen for examination and modern technique of measuring with a high temporal resolution. Under these standardised conditions the investigated parameters of the intracompartmental pressure curve should be reconsidered once more regarding diagnostic predictability by calculations of specifity and sensitivity.Einleitung: Das chronisch-funktionelle Kompartmentsyndrom des M. tibialis anterior gilt als häufigste Ursache von Unterschenkelbeschwerden bei Freizeit- und Leistungssportlern. Für die Diagnose ist die objektive dynamische Druckmessung während einer Übungsbelastung von entscheidender Bedeutung. Kontrovers wird diskutiert, welche Parameter von signifikanter Aussagekraft sind. Methodik: Metaanalyse aller 21 Studien (1979–1998), in denen der intrakompartimentelle Druckverlauf im M. tibialis anterior während Belastung gemessen wurde. Analyseparameter: Art des Provokationstests, Meßtechnik, empfohlene Grenzwerte. Ergebnisse: Die Art der gewählten Provokationstests ist uneinheitlich (isokinetische Übungen für 5–10 min, Laufbandbelastung zwischen 3,2 und 12 km/h). In 8 der 21 Studien wurden die Messungen mit der nicht geeigneten Wick-Katheter-Technik durchgeführt. Die Gesamtsicht zeigt, daß kein empfohlenes Diagnosekriterium unwidersprochen von anderen Arbeitsgruppen aufgegriffen wird. Die Druckkurvenparameter variieren zwischen den Studien um bis zu 500 %. Schlußfolgerungen: Aus den bisher vorliegenden Studien kann keine einheitliche Empfehlung für diagnostisch relevante Parameter abgeleitet werden. Zukünftige Untersuchungen sollten mit einem standardisierten und reproduzierbaren Untersuchungsregime und moderner Meßtechnik durchgeführt werden. Für die erarbeiteten Grenzwerte sollten zur Bewertung ihres prädiktiven Werts die Parameter Spezifität und Sensitivität angegeben werden.

Long-term invasive measurement of subcutaneous oxygen partial pressure above the sacrum on lying healthy volunteers

Pressure ulcers are frequently seen dermal lesions, but little is known about their pathophysiology. It is generally assumed that prolonged tissue pressure impairs blood circulation thus causing ischemic damage to tissue. Therefore, subcutaneous oxygen partial pressure was measured to confirm this hypothesis. In the past, various authors have conducted tests on healthy subjects to determine oxygen partial pressure transcutaneously during periods not exceeding 20 minutes. All found a decrease at susceptible sites, e.g., the sacrum. The present study was the first one to measure oxygen partial pressure subcutaneously above the sacrums of four test subjects during a period of 5 hours. In all cases, the values first decreased to a minimum of 37% of baseline before they returned to the initial values. This observation is in contradiction to former studies, which start from the assumption of critical ischemia due to interface pressure, measured on healthy volunteers too.

[Reduced muscular oxygen tension and nerve impulse transmission from antishock hose. Reduction of oxygen tension in the tibial muscle and impulse transmission in the peroneal nerve from pneumatic -1 pressure from antishock hose].

ZusammenfassungFragestellung und Ziel der Studie: Ziel der Arbeit ist, durch Messung des intramuskulären Sauerstoffpartialdrucks den kritischen Bereich des pneumatischen Drucks der Antischockhose (ASH) zu definieren, ab dem sich eine Muskelischämie an der unteren Extremität entwickelt. Bei gleichzeitiger intrakompartimenteller Druckmessung sollte neben der Gewebeoxygenation auch die auf Druck empfindlich reagierende Impulsfortleitung im N. peronaeus profundus beurteilt werden. Methodik: Bei 22 normotensiven gesunden Freiwilligen wurden mit einem ASH-Beinsegment im M. tibialis anterior Druckwerte zwischen 0 und 100 mm Hg erzeugt. Über einen Zeitraum von bis zu 6 h erfolgte die Messung des Muskelgewebedrucks, der Sauerstoffspannung und des Muskelsummenaktionspotentials (MSAP) des N. peronaeus profundus. Ergebnisse: Ausgangsdruckwert im M. tibialis anterior im Median 12,0 mm Hg (Q25%/Q75%: 8,9/17,3), pO2: 14,8 mm Hg (Q25%/Q75%: 11,5/22,0). Übertragung des pneumatischen Drucks zu 97,7% (Q25%/Q75%: 89,2/99,8) auf den Extremitätenmuskel. Bereits bei niedrigen ASH-Druckwerten (20–40 mm Hg) trat im Einzelfall eine schwere Hypoxie auf. Eine Reduktion des MSAP war ab einem ASH-Druck von 10 mm Hg zu beobachten. ASH-Druckwerte von 60 mm Hg (n = 6) führten in 5 Fällen innerhalb von 5–20 min zum Abfall des pO2 auf pathologische Werte. Inflationsdruckwerte über 60 mm Hg resultierten nahezu ausnahmslos in einer Anoxie des Muskels und im Verlust des MSAP. Schlußfolgerungen: Der Einsatz der ASH sollte nur mit Modellen erfolgen, bei denen der Inflationsdruck manometrisch kontrolliert werden kann. Der ASH-Einsatz erscheint dann gerechtfertigt, wenn bei einem Polytraumatisierten im schweren hämorrhagischen Schock das Risiko einer sich auch systemisch auswirkenden lokalen Gewebeischämie bewußt in Kauf genommen werden muß.AbstractObject of the study: The aim of the study was to assess, whether the pneumatic pressure of an antishock-trouser (AST) of 20–40 mm Hg induces a decreased oxygenation of the anterior tibial muscle and attenuates muscular response potential (MRP) of n. peronaeus profundus? Methods: Among 22 normotensive, healthy volunteers the AST were tested by applying pressure values between 0 and 100 mm Hg and measuring the intracompartmental pressure, the muscular oxygen pressure as well as the MRP by electroneurographic means within a period of 6 hours. Results: The median initial intracompartmental pressure value of the m. tibialis anterior was 12.0 mm Hg (Q25%/Q75%: 8.9/17.3), the muscular oxygen pressure 14.8 mm Hg (Q25%/Q75%: 11.5/22.0). Transmission of the pneumatic AST-leg segment pressure to the muscle: 97.7% (Q25%/Q75%: 89.2/99.8). Already in the low AST pressure field (20–40 mm Hg) a severe hypoxia occurred in one case. A reduction of MRP was noticed at an AST pressure rate of 10 mm Hg. In 5 of 6 cases AST pressure values of 60 mm Hg led to pathological pO2-values within 5–20 minutes. Almost without exception AST-pressure rates < 60 mm Hg resulted in an anoxia of the muscle and loss of the MRP. Conclusions: We should demand that the AST are only applied with models where the pressure generated within the single segments can be controlled by pressure gauge. The application of the AST seems to be justified for polytraumatised in severe haemorrhagic shock where the risk of a local tissue ischemia with systemical consequences must deliberately be accepted.