[Navigation in lumbar spinal surgery: When is it useful?] / Navigation bei lumbalen Eingriffen: Wann ist sie sinnvoll?

BACKGROUND: Spinal navigation has evolved greatly since its implementation in the mid-1990s and is now widely used in lumbar spine surgery. However, navigation is not yet accepted as a standard technique. APPLICATIONS: In addition to the classic use in lumbar pedicle screw instrumentation, navigation technology, especially in combination with intraoperative 3D imaging, can be applied in a wide range of indications and in all lumbar approaches. The technology is particularly helpful in minimally invasive operations. The concept of "total navigation" stands for an efficient use of the technique from skin incision on and aims at complete elimination of radiation exposure for the surgical team. ADVANTAGES AND PITFALLS: High accuracy and low radiation exposure of the OR team are indisputable advantages of navigated operations, while time savings and economic benefits are yet to be demonstrated. Regular use and standardized workflow are essential for the safe and effective application of lumbar navigation. Currently, lumbar navigation technology is already of great importance, yet the complex technology requires intensive training. With improved user comfort and image quality, spinal navigation will continue to spread in the future.

Hypothermia does not influence liver damage and function in a porcine polytrauma model.

BACKGROUND: Previous studies revealed evidence that induced hypothermia attenuates ischemic organ injuries after severe trauma. In the present study, the effect of hypothermia on liver damage was investigated in a porcine long term model of multi-system injury, consisting of blunt chest trauma, penetrating abdominal trauma, musculoskeletal injury, and hemorrhagic shockMETHODS: In 30 pigs, a standardized polytrauma including blunt chest trauma, penetrating abdominal trauma, musculoskeletal injury, and hemorrhagic shock of 45% of total blood volume was induced. Following trauma, hypothermia of 33∘C was induced for 12 h and intensive care treatment was evaluated for 48 h. As outcome parameters, we assessed liver function and serum transaminase levels as well as a histopathological analysis of tissue samples. A further 10 animals served as controls. RESULTS: Serum transaminase levels were increased at the end of the observation period following hypothermia without reaching statistical significance compared to normothermic groups. Liver function was preserved (p⩽ 0.05) after the rewarming period in hypothermic animals but showed no difference at the end of the observation period. In H&E staining, cell death was slightly increased hypothermic animals and caspase-3 staining displayed tendency towards more apoptosis in hypothermic group as well. CONCLUSIONS: Induction of hypothermia could not significantly improve hepatic damage during the first 48 h following major trauma. Further studies focusing on multi-organ failure including a longer observation period are required to illuminate the impact of hypothermia on hepatic function in multiple trauma patients.

A porcine polytrauma model with two different degrees of hemorrhagic shock: outcome related to trauma within the first 48 h.

BACKGROUND: An animal polytrauma model was developed, including trunk and extremity injuries combined with hemorrhagic shock and a prolonged post-traumatic phase. This could be useful for the assessment of different therapeutic approaches during intensive care therapy. METHODS: A standardized polytrauma including lung contusion, liver laceration and lower leg fracture was applied in 25 pigs. They underwent controlled haemorrhage either with a blood volume loss of 45 % and a median arterial pressure (MAP) <30 mmHg/90 min (group L, n = 15) or a 50 % blood loss of and an MAP <25 mmHg/120 min (group H, n = 10). Five non-traumatized pigs served as a control (group C). Subsequently, intensive care treatment was given for an observational period of 48 h. RESULTS: Both trauma groups showed signs of shock and organ injury (heart rate, MAP and lactate). The frequency of cardiopulmonary resuscitation (CPR) and lung injury was directly related to the severity of the haemorrhagic shock (CPR-group L: 4 of 15 pigs, group H: 4 of 10 pigs; Respiratory failure-group L: 3 of 13, group H: 3 of 9. There was no difference in mortality between trauma groups. CONCLUSION: The present data suggest that our model reflects the mortality and organ failure of polytrauma in humans during shock and the intensive care period. This suggests that the experimental protocol could be useful for the assessment of therapeutic approaches during the post-traumatic period.

Randomized controlled trials in neurosurgery--how good are we?

BACKGROUND: The strongest evidence in medical clinical literature is represented by randomized controlled trials (RCTs). This study was designed to evaluate neurosurgically relevant RCTs published recently by neurosurgeons. METHOD: A literature search in MEDLINE and EMBASE included all clinical studies published up to 30 June 2006. RCTs with neurosurgical relevance published by at least one author with affiliation to a neurosurgical department were selected. The number and characteristics of individual trials were recorded, and the quality of the trials with regard to study design, quality of reporting, and relevance for clinical practice was assessed by two different investigators using a modification of the Scottish Intercollegiate Guidelines Network methodology checklist. Changes of RCT quality over time as well as factors influencing the quality were analyzed. FINDINGS: From the initial search results (MEDLINE n = 3,860, EMBASE n = 3,113 articles), 159 RCTs published by neurosurgeons were extracted for final evaluation. Of the RCTs, 62% have been published since 1995; 52% came from the USA, UK, and Germany. The median RCT sample size was 78 patients and the median follow-up 35.7 weeks. Fifty-two percent of all RCTs were of good, 37% of moderate, and 11% of bad quality, with an improvement over time. RCTs with financial funding and RCTs with a sample size of >78 patients were of significantly better quality. There were no major differences in the rating of the studies between the two investigators. CONCLUSIONS: Only a fraction of neurosurgically relevant literature consists of RCTs, but the quality is satisfying and has significantly improved over the last years. An adequate sample size and sufficient financial support seem to be of substantial importance with regard to the quality of the study. Our data also show that by using a standardized checklist, the quality of trials can be reliably assessed by observers of different experience and educational levels.

Surgical resection plus stereotactic 125I brachytherapy in adult patients with eloquently located supratentorial WHO grade II glioma - feasibility and outcome of a combined local treatment concept.

OBJECTIVE: The current pilot study analyzed feasibility, risk and effectiveness of 1) microsurgery plus stereotactic iodine-125 ((125)I) brachytherapy (SBT) for large (diameter > 4 cm), circumscribed, and complex located WHO grade II glioma and 2) SBT alone for small (diameter < 4 cm), and complex located recurrences. METHODS: Lowactivity temporary (125)I seeds were used. The applied reference dose was 54 Gy and the dose rate was low (median, 10 cGy/h). Time to progression and time to additional external beam radiation (EBR) and/or chemotherapy were estimated with the Kaplan-Meier method. Any adverse sequel potentially attributable to treatment was classified as morbidity. Treatment effects of SBT were estimated according to the modified MacDonald criteria. RESULTS: Thirtyone patients (de novo group: n = 18, recurrence group: n = 13) were included. The median tumor volume before surgery was 66 ml. A planned partial tumor resection achieved eligibility for SBT in all patients. Transient morbidity of microsurgery and SBT was 27.8 % and 6.4 %, respectively. There was no permanent morbidity. Radiogenic complications did not occur. Complete response, partial response, and stable disease were seen in 8, 9, and 14 patients, respectively. Ten patients exhibited tumor progression (overall 5-year progression- free survival > 60 %). The 5-year probability to receive chemotherapy and/or EBR was 18 %. CONCLUSION: A planned partial tumor resection of large and complex located WHO grade II glioma is safe. SBT of small and complex located residual of recurrent tumors is safe and minimally invasive. Combined treatment may provide the possibility to withhold EBR and/or chemotherapy for a considerable number of patients and deserves further prospective evaluation.

[Pharmacokinetics of articaine in mandibular nerve block]. / Pharmakokinetik von Articain bei der Nervus mandibularis-Blockade.

Up to now, mandibular nerve blocks have been carried out without knowing the exact blood concentrations resulting from the use of the local anesthetics. Due to the high vascularity a rapid increase in serum local anesthetic levels is to be expected. Due to analytical problems, the literature provides controversial statements about the pharmacokinetics of articaine which is generally used for this block. The given half-life periods following intramuscular application range from 39 min [8] to 31 h [6]. For this reason, mandibular nerve blocks with 2 ml 4% articaine with 1:200,000 epinephrine were carried out in 10 awake patients and 10 patients during intubation anesthesia. RESULTS. Blood samples from peripheral veins showed an average maximum concentration of 2.1 +/- 1.3 mg/l after 12.5 +/- 2.5 min. After 8 h the value had fallen below the minimum detection limit of 0.05 mg/l. In the present study, a half-life of approximately 20 min was determined for articaine after conduction anesthesia. This local anesthetic holds an exceptional position because as an amide-type local anesthetic it contains an additional ester group that is hydrolytically metabolized in the blood. The concentration of the resulting metabolite reaches a maximum value of 2.6 +/- 1.6 mg/l after 40 to 50 min. CONCLUSIONS. Compared to other amide-type local anesthetics, whose terminal plasma half-life varies between 1 and 3.6 h [5], the value of 20 min found for articaine is very low. This is in part due to its structure, as the ester group is rapidly metabolized by plasma esterases. Because of its rapid breakdown articaine is very suitable for use in oral surgery. The HPLC method represents an uncomplicated analytical technique for the determination of local anesthetics levels in blood and other body fluids.

[Influence of the volume of peridural morphine bolus injections on morphine concentration in the cisterna magna of the dog]. / Zum Einfluss des Volumens periduraler Morphinbolusinjektionen auf die Morphinkonzentration in der Zisterna magna des Hundes.

14 dogs received randomly a bolus injection of either 2 mg morphine in 10 ml isotonic saline solution or 2 mg morphine in 1 ml isotonic saline solution epidurally at T6. An epidural infusion of 0.16 mg morphine/0.06 ml/h was applied immediately following the 1 ml bolus injection of morphine. Cisternal cerebellomedullary CSF samples were taken at varying intervals to determine free morphine immunoreactivity by radioimmunoassay. Within 20 min after the 10 ml bolus injection the peak CSF morphine concentration of 3594 +/- 910 ng/ml was reached. Following this, CSF morphine levels decreased exponentially and after 48 h 8 +/- 3 ng/ml were measured. The peak CSF morphine concentration of 139 +/- 51 ng/ml was, however, reached only after 2 h following the 1 ml bolus injection plus the infusion treatment. Despite the additional infused amount of 7.68 mg over 48 h the CSF morphine concentrations decreased also exponentially and after 48 h 16 +/- 4 ng/ml were measured. One may conclude, therefore, that the risk of respiratory depression is negligible under epidural infusion treatment following an initial "Low-Volume"-bolus injection of 2 mg morphine, a recommendable method for treating post-operative pain. High-volume bolus injections of morphine should generally be abandoned in epidural treatment of pain.

Critical analysis of height reduction in oestrogen-treated tall girls.

Twenty-one girls with familial tall stature were reevaluated at 18 years of age. Fourteen of them had been treated with high-dose oestrogens (I), while seven girls had not been treated (II). The untreated group is comparable but not a strict control group. Recordings on initiation of the study were: Chronologic age: 12.0 +/- 1.4 (I) versus 13.5 +/- 1.5 years (II; means +/- SD), Bone age: (1) Greulich-Pyle: 11.8 +/- 1.4 (I) versus 13.1 +/- 1.1 years (II), (2) Tanner-Whitehouse II: 12.7 +/- 1.0 (I) versus 13.6 +/- 1.1 years (II). Mean height predictions according to (1) Bayley-Pinneau, (2) Roche-Wainer-Thissen and Tanner (3) with, and (4) without allowance for mid-parent height ranged from 179.4-184 (I) to 175.7-179.5 cm (II). In the treated group there was an average reduction of predicted height of between 2.3 and 6.5 cm, depending on which of the four methods was used. In the untreated group the average differences between calculated and observed mature height varied from 0.2-3.4 cm. The difference in the reduction of predicted height between the treated and untreated groups was significant (P less than 0.05) only with the Bayley-Pinneau method and not with the others. In the treated group highly significant correlations were found between height reduction and the initial chronologic age, bone age and duration of therapy.

[Is calcium indicated in resuscitation? Experimental studies in dogs]. / Hat Calcium in der Reanimation eine Berechtigung? Experimentelle Untersuchungen an Hunden.

This study compares the effect of epinephrine (11 dogs) with that of the combination of epinephrine with calcium (10 dogs) in CPR after anoxial cardiac arrest. In the epinephrine group resuscitation was successful in all 11 dogs within 4 minutes. In the calcium group only 7 out of 10 dogs could be resuscitated: 3 dogs died during CPR in cause of irreversible fibrillation (2 cases) and "stone heart" (1 case). High CPK-activity reflected severe myocardial cell damage. In the survivors of the calcium group cardiac function was significantly impaired: 1. decreased left ventricular pressure (LVP) and contractility (dp/dt max), 2. increased afterload, 3. decreased cardiac output inspite of increased heart rate, 4. as a consequence, reduced perfusion of the vital organs. - These results foster the conclusion that calcium should not be used henceforth in CPR. Epinephrine was and is still the drug of choice in resuscitation after cardiac arrest.

[Are beta-sympathomimetic substances in resuscitation useful? Experimental studies]. / Sind beta-sympathikomimetische Substanzen in der Reanimation sinnvoll? Experimentelle Untersuchungen.

Orciprenaline and epinephrine have been compared in cardiopulmonary resuscitation (CPR) in the dog. In a third group no substance was given. When orciprenaline was repeated without success, epinephrine was given. After administration of epinephrine left ventricular pressure and central aortic pressure were significantly higher. CPR was also more successful in epinephrine-treated dogs, a fact which can be attributed directly to these higher pressures. However, the attempt at resuscitation with orciprenaline, and, in the event of failure, with epinephrine, yielded significantly poorer results than treatment with epinephrine alone. Epinephrine substantially increased coronary perfusion pressure and coronary blood flow was adequate. When orciprenaline was administered, however, diastolic blood pressure decreased and no coronary blood flow could be measured. Serum CPK activity was increased. Ventricular fibrillation occurred just as often with epinephrine as with orciprenaline. In the epinephrine group defibrillation led directly to adequate circulation, whereas in the orciprenaline group subsequent electromechanical dissociation was observed. It is concluded that beta-receptor stimulators have no place in CPR. Epinephrine is the drug of choice in resuscitation after cardiac arrest.

[Axillary plexus anesthesia in noncooperative patients]. / Axilläre Plexusanaesthesie bei nicht kooperativen Patienten.

In 36 non-cooperative patients we performed block of the axillary brachial plexus by using a well recognized catheter technique. A flexible, disposable intravenous cannula was placed into the axillary neurovascular sheath and used for injection of local anaesthetic solution without adverse sequelae. Analgesia for acute and elective surgical procedures was obtained rapidly and independent of any patient's assistance in all cases. Catheter axillary block seems to be a valuable anaesthetic technique in the difficult and risky management of non-cooperative patients.

[Orciprenaline (Alupent) in resuscitation for circulatory arrest? Experimental comparison between orciprenaline and adrenaline in dogs]. / Orciprenalin (Alupent) in der Reanimation nach Kreislaufstillstand? Experimenteller Vergleich zwischen Orciprenalin und Adrenalin an Hunden.

This study compares CPR with orciprenaline (8 dogs), with epinephrine (11 dogs) and without any drug (8 dogs) in cardiac arrest caused by anoxia. Resuscitation was successful in all animals of the epinephrine group and in 2 of the orciprenaline group. Spontaneous circulation could not be restored in any of the control animals. There was no difference in the occurrence of ventricular fibrillation between the drug groups. No fibrillation occurred in the controls. On the other hand, the incidence of successful defibrillation was significantly higher with epinephrine. The superiority of epinephrine was due to its having effected a significantly higher diastolic pressure during cardiac massage. The diastolic pressure decreased after orciprenaline injection to such an extent that coronary underperfusion resulted with consequent rise of serum CPK. We conclude that the use of orciprenaline is contraindicated in cardiac arrest.

[The metabolism of halothane under the influence of thiopental, methohexital, etomidate, enflurane and disulfiram under clinical conditions (author's transl)]. / Der Halothanstoffwechsel unter dem Einfluss von Thiopental, Methohexital, Etomidat, Enflurance und Disulfiram bei klinischen Bedingungen.

The biotransformation of halothane is supposed to be the cause of the rare "halothane-hepatitis". Therefore an inhibition of the metabolism of Halothane is of some interest. We used bromide as a metabolite of Halothane and investigated the bromide level of the serum of patients after halothane anaesthesia by means of x-ray fluorescence spectrometry. The induction of anaesthesia with Thiopental, Methohexital and Etomidate had no influence on the bromide level. Likewise the influence of Enflurane on the metabolism of Halothane was not significant. An effective inhibitor in man is Disulfiram. The authors assume, that further information about the toxicity of Halothane metabolites can be gained through further studies of drugs like Disulfiram.

The use of serum cholinesterase in succinylcholine apnoea.

Fifteen patients demonstrating unexpected prolonged apnoea lasting several hours after succinylcholine have been treated by a new preparation of human serum cholinesterase. Adequate spontaneous respiration was re-established in an average period of ten minutes after the injection. In 12 patients biochemical genetic examinations confirmed the presence of an atypical serum cholinesterase. In three patients none of the usual variants were found. It is therefore supposed that other unknown variants of serum cholinesterase exist which cannot hydrolyze succinylcholine. The use of serum cholinesterase in succinylcholine apnoea provided considerable relief to both patient and anaesthetist.