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The definition of spinal instability is still controversial. For this reason, it is essential to better understand the difference in biomechanical behaviour between healthy and degenerated human spinal segments in vivo. A novel computer-assisted instrument was developed with the objective to characterize the biomechanical parameters of the spinal segment. Investigation of the viscoelastic properties as well as the dynamic spinal stiffness was performed during a minimally invasive procedure (microdiscectomy) on five patients. Measurements were performed intraoperatively and the protocol consisted of a dynamic part, where spinal stiffness was computed, and a static part, where force relaxation of the segment under constant elongation was studied. The repeatability of the measurement procedure was demonstrated with five replicated tests. The spinal segment tissues were found to have viscoelastic properties. Preliminary tests confirmed a decrease in stiffness after decompression surgery. Patients with non-relaxed muscles showed higher stiffness and relaxation rate compared to patients with relaxed muscles, which can be explained by the contraction and relaxation reflex of muscles under fast and then static elongation. The results show the usefulness of the biomechanical characterization of the human lumbar spinal segment to improve the understanding of the contribution of individual anatomical structures to spinal stability.

Objective: To test a new tiny-tipped intraoperative diagnostic tool that was designed to provide the surgeon with reliable stiffness data on the motion segment during microdiscectomy. A decrease in stiffness after nuclectomy and a measurable influence of muscle tension were assumed. If the influence of muscle tension on the motion segment could at least be ruled out, there should be no difference with regard to stiffness between women and men. If these criteria are met, this new intraoperative diagnostic tool could be used in further studies for objective decision-making regarding additional stabilization systems after microdiscectomy., Methods: After evaluation of the influence of muscle relaxation during in vivo measurements with a spinal spreader between the spinous processes, 21 motion segments were investigated in 21 patients. Using a standardized protocol, including quantified muscle relaxation, spinal stiffness was measured before laminotomy and after nuclectomy., Results: The decrease in stiffness after microdiscectomy was highly significant. There were no statistically significant differences between men and women. The average stiffness value before discectomy was 33.7 N/mm, and it decreased to 25.6 N/mm after discectomy. The average decrease in stiffness was 8.1 N/mm (24%)., Conclusion: In the moderately degenerated spine, stiffness decreases significantly after microdiscectomy. Control for muscle relaxation is essential when measuring in vivo spinal stiffness. The new spinal spreader was found to provide reliable data. This spreader could be used in further studies for objective decision-making about additional stabilization systems after microdiscectomy.

Object: The authors conducted a study to determine the thread properties that provide optimal screw fixation in cancellous bone, when screws of the same external screw diameter are used., Methods: Three compliance engineering-certified screws in clinical use, all of the same external diameter and length, were compared in an axial pullout experiment with respect to advantageous thread properties. As test material, standardized Sawbone blocks with 3 different densities (0.12, 0.16, and 0.32 g/cm3) were used., Results: Screw thread Type 1, whose flank overlap area (FOA; 261 mm2) results from narrowing the conical core in the thread area, showed significantly better holding strength than the other types. Screw thread Type 2 (FOA 326 mm2) with a conical but thicker core and a smaller thread pitch was found to be the only one without increase of pull-out forces when test materials density changed from 0.12 to 0.16 g/cm3. A screw tested as control, with a constant (cylindrical) core diameter (Type 3; FOA 206 mm2), had the same thread pitch as Type 1 but without the compressive effect on the surrounding bur hole wall material. Nevertheless, it showed higher pullout forces in the 0.16-g/cm3 material than screw Type 2., Conclusions: By reducing the core diameter of a screw toward the tip, while maintaining a constant nominal (external) diameter, one achieves frictional connection due to compression of surrounding material. In addition, the FOA is increased, which, in summary, leads to better fixation, as shown by screw Type 1.

Background and Objective: Continuous epidural administration of a local anesthetic drug for postoperative pain treatment of patients, who undergo a fusion operation of lumbar vertebrae is limited by the suction of wound drainage. The effect of the single epidural administration of levobupivacaine 0.25% 10 mL 20 minutes before finishing of skin closure was examined on the postoperative demand for piritramide., Methods: The study was conducted in a prospective, single blind and randomized manner. Forty patients scheduled for posterior intervertebral body fusion of two or three vertebrae were divided into two groups. Group A received levobupivacaine 0.25% 10 mL epidurally, Group B received piritramide 0.08 mg kg(-1) i.v. Time of administration was 20 minutes before predicted finish of skin closure in both groups. Piritramide was administered intravenously to achieve a VAS of 3 or less during the phase of awakening. After regaining of co-operativity, piritramide was self administered via PCA pump. VAS and the demand of piritramide within 12 hours postoperative were recorded., Results: VAS at the time of being approachable (P = 0.23), VAS at the time of regaining co-operativity (P = 0.53) and VAS 12 hours postoperative (P = 0.27) did not differ significantly. The postoperative demand of piritramide was significantly lower in Group A (0.36 +/- 0.25 mg kg(-1) vs. 0.52 +/- 0.19 mg kg(-1) in Group B) (P = 0.026)., Conclusion: The epidural administration of levobupivacaine 0.25% 10 mL 20 minutes before finishing of skin closure effects opioid sparing in the pain treatment of patients undergoing posterior interbody fusion of two or three vertebrae.

Objectives: Although previous research has shown that certain medical data and psychosocial factors predict postoperative pain, it remains unclear whether they also contribute to a more distinct outcome measure that is based on classification of self-reported outcome criteria. To assess the prognostic power of somatic, psychologic, and social predictors when evident outcome criteria of surgical treatment are investigated, this study used a prospective longitudinal design examining preoperative factors associated with outcome six months after lumbar discectomy., Methods: Forty-eight out of 58 consecutive patients were included (60% male, 40% female, mean age 47 years). Preoperative data comprised of Lasegue sign (straight leg raising test), pain duration, paresis and radicular distribution, depression, pain disability, pain coping strategies, and qualitative descriptions of pain. Additionally, sociodemographic and occupational characteristics were observed. Six months' postoperative classification of outcome included pain intensity, pain locations, functional capacity, return to work, and health-related quality of life., Results: From a surgical point of view, lumbar discectomy was successfully carried out on all patients. But, when subjective criteria of outcome were investigated, 56% of patients benefited from lumbar discectomy, whereas 44% of patients had poor results. Lasegue sign, depression, and sensory pain descriptions proved to be significant predictors, whereas pain cognition and pain coping strategies had no significant influence on evident outcome classification., Discussion: Classification of patients regarding their individual outcome profiles showed that patients responded differently to lumbar disc-surgery. High risk factors for poor outcome of surgery are Laseque-sign and depression.

Background: The development of a secondary neoplasm in childhood cancer survivors attains growing importance due to the reported excellent survival and therefore the long exposure to potentially carcinogenic effects of treatment., Case Report: We report a 14-year-old girl in whom a large craniopharyngioma (CP) was diagnosed. After surgery, radiation therapy (RT) was given for residual tumour. Discrete progression necessitated further surgery, resulting in permanent tumour control. Soon after the second surgery hypothalamic-pituitary dysfunction developed together with obesity. Supportive hormone therapy was initiated. Growth hormone (GH) therapy was also given for 15 months. Four years after the diagnosis, a cerebropontine anaplastic astrocytoma WHO grade III was detected, with the main lesion being at the dorsal edge of the irradiated area. The girl died 1 month later from this secondary presumably radiation-induced tumour. Only recently a second child with RT for a CP was diagnosed with malignant glioma in our hospital. CASE REPORTS IN THE LITERATURE: 12 other cases of malignant glioma have been reported after RT for CP. Including our present cases, the mean latency period was 10.7 years (median 9.6 years). However, the shortest latency periods were found in patients who had received GH therapy. In numerous cases, the secondary tumour was seen at the edge of the irradiated volume, and not in the region with the highest absorbed dose., Conclusions: Therapy-induced secondary gliomas after treatment of CP or other intracranial tumours are rare but dramatic late events with a very poor prognosis. Including our own 2 patients, we reviewed 14 cases of CP with occurrence of a secondary, probably radiation-induced malignant glioma. The short latency periods for patients treated with GH is remarkable. We therefore suspect that GH therapy may accelerate the development of a secondary brain tumour. We are reluctant to recommend GH therapy in conventionally irradiated CP patients. In order to seriously answer the questions about therapy-induced secondary neoplasms, a life-long follow-up is mandatory for all patients who are survivors of childhood cancer., (Copyright 2001 S. Karger GmbH, Freiburg)

Purpose: This study evaluated the use of polyglactin 910-polydioxanon (PPP) for repair of orbital roof defects., Patients and Methods: Between 1988 and 1996, 144 patients treated in the Department of Neurosurgery, Christian-Doppler-Medical-Center Salzburg, were operated on transcranially for fractures of the orbital roof or intraorbital tumors. In 85 of these 144 patients, PPP was used for reconstruction of the orbital roof or closure of the periorbita. The postoperative results in patients in whom the PPP patch was used for reconstruction of the orbital roof were compared with the results of a group treated without PPP., Results: Even in severely injured patients, the reconstruction was judged to be very good in 71 patients (83.5%)., Conclusion: PPP is a useful material for the reconstruction of the orbital roof.

In a retrospective study the operative results of 200 patients with chronic subdural hematoma were investigated. In the majority of patients a burr hole and a closed drainage was performed. The operative result was very good (resumption of normal life) in 67.5% of the patients. Operative mortality was 4.5%, in these patients an obvious connection was appearant between the result and the poor preoperative condition. The recurrence of hematomas required a second operation in 8% and a third in 1%.

In a retrospective study, we analyzed the operative results of 300 patients over 60 years with hypertensive intracerebral hemorrhages treated from September 1981 to June 1995 at the Department of Neurosurgery, Landesnervenklinik Salzburg. The patients underwent surgery for hypertensive hemorrhages measuring 30 mm or more on CT scan. The postoperative results were assessed by the Glasgow Outcome Score, which showed that the postoperative mortality was 31.3%; 22% of the patients made a good or very good recovery. The mode of selecting the intracerebral hematomas by size and location to achieve good results with surgical treatment is discussed. The authors consider surgery beneficial for selected cases.

In a retrospective study the prognosis of acute subdural hematoma was considered with reference to the data of 255 patients who underwent surgery because of acute subdural hematoma during a period of 10 years in the Department of Neurosurgery of the Landesnervenklinik in Salzburg. The mortality rate was 43.5%, and 21.6% had a full functional recovery. The findings of the study confirm that the preoperative neurological condition, the age, the kind of accident sustained and the extent of concomitant brain injury influence on the prognosis decisively.

Repositioning of fractured fragments, stabilization with miniplates and reconstruction using autologous bone are commonly used techniques in the treatment of fractures of the orbital roof. Between 1988 and 1993, 101 patients were operated upon transcranially in the Department of Neurosurgery of the Landesnervenklinik Salzburg, for fractures of the orbital roof. The method, the timing and the results of treatments are presented. It can be demonstrated that even in severely injured patients the results were good in 79.2% (80 patients).

The possible treatments for dislocated fractures of the orbital roof range from reduction of the fracture fragments, and reconstruction and stabilisation with miniplates, to plastic surgery using autologous bone. Between 1988 and 1994, 105 patients treated in the Department of Neurosurgery of the Landesnervenklinik Salzburg were operated on transcranially for fractures of the orbital roof. The methods of treatment, the timing of treatment, and the results are discussed. It is shown that even in severely injured patients the results were good in 83 patients (79%).

In a retrospective study the clinical symptomatology and the clinical results of carpal tunnel syndrome is evaluated by means of 1000 patients. The results of 1047 operated hands assessed by the patients were rated as very good 72%, good 21.2% and satisfactory 5.6%.

Intracranial arteritis due to fungal infection is an uncommon complication of neurosurgical operations. A 36-year-old female developed arteritis caused by Aspergillus fumigatus at the site of the temporary clip following the clipping of an initially uncomplicated intracranial aneurysm. The inflammatory, slowly progressing vascular occlusion mimicked the vasospasm common in subarachnoid hemorrhage.

The value of perioperative prophylactic use of antibiotics in lumbar disc surgery is investigated, based on a retrospective study of the operative results of 5041 patients. The rate of occurrence of postoperative spondylodiscitis was significantly higher during the period in which no perioperative prophylaxis was carried out, than it was during the period, in which perioperative prophylaxis was routine. Thus the perioperative prophylactic use of antibiotics seems highly recommendable.

The timing of operation can be especially difficult when frontobasal fractures are combined with other head injuries and midfacial injuries. In these cases, the head injury represents a considerable hazard to the patient and therefore it is mandatory to avoid any additional strain that might be caused by treating the midfacial injury first. On the other hand, because of poorer results with the secondary treatment, the surgical therapy for midfacial injuries should be achieved as early as possible. This report describes the results obtained in 68 patients managed over a period of 5 years and discusses their definite primary treatment. It emphasizes the need for close cooperation between the various surgical specialties involved.

In a retrospective study 368 epidural hematomas are presented, treated from 1970 until August 1991. The clinical course and manifestation of acute epidural hematomas is commented on by means of own cases. Assessing the success of treatment, it could be demonstrated that the prompter diagnosis reduced the lethal outcome of epidural hematoma to 6.6%.

Craniocerebral missile injuries are a relatively rare type of head injury during peacetime. In the Department of Neurosurgery of the Landesnervenklinik Salzburg 72 patients were operated on for gunshot wounds of the brain in the period 1970-1990, and 31 survived. In the same period 6763 patients were treated for other head injuries. As shown by the clinical courses and the operative results, the velocity and thus the extent of the primary brain damage determine the prospects of success in the treatment of cerebral missile injuries.

Intracranial aneurysms are an uncommon manifestation of fungal infection. A case is described in which the formation of an aneurysm followed an intracranial intraoperative Aspergillus infection attributable to a long period of preoperative antibiotic medication and immunosuppressive therapy with steroids.

Posttraumatic intracranial hematomas of the posterior fossa are rare but severe complications of head injuries. In the period between 1970 and 1989 in the neurosurgical department of Landesnervenklinik Salzburg 28 patients were operated on posttraumatic hematomas of the posterior fossa. The prognosis of this type of injury is shown by the own results.

An increasing number of neurosurgeons, neurologists and anesthesiologists is concerned with the diagnostic securing of brain death, because of the advance of intensive care and the possibility of transplantation of organs. In this, by legal issues considerable influenced field, the documentation represents an important point. Besides an efficient organisation should avoid unnecessary loss of time by the explanation of organs.

Posttraumatic dural arterio-venous malformations, as described in this case, are a rare incidence of head injury. Because of possible further complications, like spontaneous bleeding or a possible increase in size, the removal is advised.

Over a period of 6 months 250 patients were operated on for lumbar disc prolapse, 125 patients each receiving prophylactic antibiotic therapy or only local, intra-operative administration of povidone-iodine. The analysis of variance showed a significant difference between the patient group treated with the antiseptic and the prophylactic antibiotic group. More abscesses and signs of infection occurred in the antibiotic treated group. Animal studies are also described.

A calcified fibroma caused a so called cervical syndrome not responding to medical treatment. In the computerized tomography a compression of the cervical spinal cord could be demonstrated. From this the indication for the operation was given.

The microbicide Polyvinylpyrrolidon-Jod-Komplex (P.J.K.) was experimentally evaluated for its use in local lavage of the epidural space. In 20 rabbits a lumbar laminectomy was performed followed either by local lavage with P.J.K. or with NaCl. After one month the meningeal covering of the operated spinal cords revealed no signs of fibrosis or arachnoid adhesions when studied macroscopically or by scanning electron microscopy (SEM).