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Management of neurotrauma by surgeons and orthopedists in a military operational setting

Uwe Max Mauer and Ulrich Kunz

There is a considerable discrepancy between the potential demand for neurosurgeons and the actual availability of such specialists not only in civilian settings but even more so in military operational environments.

For this reason, the Department of Neurosurgery at the German Armed Forces Hospital in Ulm conducts courses for surgeons and orthopedists on the management of patients with neurotrauma. Twelve such courses have already taken place. Each course lasts 1 week. Participants can expect to gain the theoretical knowledge and practical skills they need to provide initial surgical care for patients with traumatic brain injuries and/or spinal trauma. Surgical techniques are practiced above all in pig and human cadavers. At the end of the course, participants with previous surgical knowledge should be able to independently perform a craniotomy, from the planning of the procedure to the closure of the wound. Former course participants have successfully used their neurosurgical knowledge in countries of deployment where they managed patients during teleconsultation sessions and helped repatriate, or even provided surgical treatment to, patients with traumatic brain injuries. In these situations, it was particularly helpful when the physician deployed abroad and the neurosurgeon in Germany knew each other personally. In the future, efforts will be made to combine telemedicine and neuronavigation in an attempt to further improve direct support for physicians under military deployment conditions.

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More malfunctioning Medos Hakim programmable valves: cause for concern?

Clinical article

Uwe Max Mauer and Ulrich Kunz

Object

In recent years, the authors have noticed a growing number of programmable valve defects at their institution. Therefore, they conducted this study to evaluate the increased incidence of malfunctioning valves.

Methods

They investigated all revisions that had been performed at their institution between 1994 and 2010 for dislodgement of the stator of a standard Medos Hakim programmable valve with a prechamber.

Results

Fifteen valves were removed because of dislodged stators. The valves had been implanted between May 16, 1993, and December 27, 2002, and were explanted between February 19, 2006, and January 22, 2010. Thus, the valves had been in place for a mean period of 11 years (median 11 years, range 7–14 years). The percentage of dislodged stators was almost 3% (15 of 546 valves). Particularly noteworthy is that all malfunctioning valves were found in children who had been younger than 1 year of age at the time of implantation.

Conclusions

Medos Hakim programmable valve malfunctions are rare events but should receive careful attention. When the pressure setting cannot be adjusted, a malfunction should always be suspected and radiographic imaging should be performed to assess the valve. Stator dislodgement is the most serious form of valve adjustment failure.

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Spine surgery in the International Security Assistance Force Role 3 combat support hospital in Mazar-e-Sharif, northern Afghanistan, 2007–2014

Chris Schulz, Uwe Max Mauer, Renè Mathieu, and Gregor Freude

OBJECTIVE

Since 2007, a continuous neurosurgery emergency service has been available in the International Security Assistance Force (ISAF) field hospital in Mazar-e-Sharif (MeS), Afghanistan. The object of this study was to assess the number and range of surgical procedures performed on the spine in the period from 2007 to 2014.

METHODS

This is a retrospective analysis of the annual neurosurgical caseload statistics from July 2007 to October 2014 (92 months). The distribution of surgical urgency (emergency, delayed urgency, or elective), patient origin (ISAF, Afghan National Army, or civilian population), and underlying causes of diseases and injuries (penetrating injury, blunt injury/fracture, or degenerative disease) was analyzed. The range and pattern of diagnoses in the neurosurgical outpatient department from 2012 and 2013 were also evaluated.

RESULTS

A total of 341 patients underwent neurosurgical operations in the period from July 2007 to October 2014. One hundred eighty-eight (55.1%) of the 341 procedures were performed on the spine, and the majority of these surgeries were performed for degenerative diseases (127/188; 67.6%). The proportion of spinal fractures and penetrating injuries (61/188; 32.4%) increased over the study period. These spinal trauma diagnoses accounted for 80% of the cases in which patients had to undergo operations within 12 hours of presentation (n = 70 cases). Spinal surgeries were performed as an emergency in 19.8% of cases, whereas 17.3% of surgeries had delayed urgency and 62.9% were elective procedures. Of the 1026 outpatient consultations documented, 82% were related to spinal issues.

CONCLUSIONS

Compared to the published numbers of cases from neurosurgery units in the rest of the ISAF area, the field hospital in MeS had a considerably lower number of operations. In addition, MeS had the highest rates of both elective neurosurgical operations and Afghan civilian patients. In comparison with the field hospital in MeS, none of the other ISAF field hospitals showed such a strong concentration of degenerative spinal conditions in their surgical spectrum. Nevertheless, the changing pattern of spine-related diagnoses and surgical therapies in the current conflict represents a challenge for future training and material planning in comparable missions.

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The Hakim programmable valve: reasons for reprogramming failures

Uwe Max Mauer, Jens Schuler, and Ulrich Kunz

Object

In patients with hydrocephalus, the pressure settings of a Medos Hakim programmable valve may require adjustments even months after implantation. In some cases, however, adjustment proves to be impossible. The object of this study was to illuminate the reasons for reprogramming failures.

Methods

Data pertaining to the authors' experience with programmable valves at their clinic were obtained through retrospective review of patient records from 1992 to 1998 and prospectively collected from 1998 to 2006. Between 1992 and 2006, 585 Medos Hakim programmable valves were implanted at the authors' center, and reprogramming failure was observed in 12 of these 585 cases. The authors investigated and recorded the reasons for reprogramming failure. In cases in which the valves had to be explanted, the valves were returned to the manufacturer for further investigation and the results were recorded.

Results

In three of the 12 cases of reprogramming failure, the pressure settings could eventually be adjusted by placing the transmitter upside down against the flow direction. In the remaining nine cases, the valve had to be removed, yielding a rate of valve explantation of approximately 1.5% in this series. In two of these nine cases, the valve was found to be rotated longitudinally along its axis. In two cases the ratchet wheel had become loose and in one the radiopaque marker had become dislodged from the baseplate. Extensive deposits were identified macroscopically and microscopically within four explanted valves.

Conclusions

The reasons for failed reprogramming of Codman Medos Hakim valves as described in this article have not been mentioned in the literature so far. Failure of adjusting the pressure setting is a very rare event in a Medos Hakim programmable valve. The programming and adjustment mechanism appears to be very reliable. Valve replacement was required due to failed reprogramming in only a few cases.

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German military neurosurgery at home and abroad

Uwe Max Mauer, Chris Schulz, Ronny Rothe, and Ulrich Kunz

For many years, the experience of neurosurgeons from the German Armed Forces was limited to the peacetime care of patients in Germany. In 1995, German military neurosurgeons were deployed abroad for the first time. Since the beginning of the International Security Assistance Force mission, there has been a rapidly increasing number of opportunities for military neurosurgeons to broaden their experience during deployments abroad.

Since the first deployment of a neurosurgeon to the German field hospital in Mazar-e-Sharif, Afghanistan, a total of 140 neurosurgical procedures have been performed there. Sixty-four surgeries were performed for cranial or spinal neurotrauma management. During the entire period, only 10 International Security Assistance Force members required acute or urgent neurosurgical interventions. The majority of neurosurgical procedures were performed in Afghan patients who received acute and elective treatment whenever the necessary infrastructure was available in the field hospital. Fifteen patients from the Afghan National Army and Police and 115 local patients underwent neurosurgery. Sixty-two procedures were carried out under acute or urgent conditions, and 78 operations were elective.

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Treatment of unresectable skull base meningiomas with somatostatin analogs

Chris Schulz, René Mathieu, Ulrich Kunz, and Uwe Max Mauer

Object

The standard surgical treatment for meningiomas is total resection, but the complete removal of skull base meningiomas can be difficult for several reasons. Thus, the management of certain meningiomas of the skull base—for example, those involving basal vessels and cranial nerves—remains a challenge. In recent reports it has been suggested that somatostatin (SST) administration can cause growth inhibition of unresectable and recurrent meningiomas. The application of SST and its analogs is not routinely integrated into standard treatment strategies for meningiomas, and clinical studies proving growth-inhibiting effects do not exist. The authors report on their experience using octreotide in patients with recurrent or unresectable meningiomas of the skull base.

Methods

Between January 1996 and December 2010, 13 patients harboring a progressive residual meningioma (as indicated by MR imaging criteria) following operative therapy were treated with a monthly injection of the SST analog octreotide (Sandostatin LAR [long-acting repeatable] 30 mg, Novartis). Eight of 13 patients had a meningioma of the skull base and were analyzed in the present study. Postoperative tumor enlargement was documented in all patients on MR images obtained before the initiation of SST therapy. All tumors were benign. No patient received radiation or chemotherapy before treatment with SST. The growth of residual tumor was monitored by MR imaging every 12 months.

Results

Three of the 8 patients had undergone surgical treatment once; 3, 2 times; and 2, 3 times. The mean time after the last meningioma operation (before starting SST treatment) and tumor enlargement as indicated by MR imaging criteria was 24 months. A total of 643 monthly cycles of Sandostatin LAR were administered. Five of the 8 patients were on SST continuously and stabilized disease was documented on MR images obtained in these patients during treatment (median 115 months, range 48–180 months). Three of the 8 patients interrupted treatment: after 60 months in 1 case because of tumor progression, after 36 months in 1 case because of side effects, and after 36 months in 1 case because the health insurance company denied cost absorption.

Conclusions

Although no case of tumor regression was detected on MR imaging, the study results indicated that SST analogs can arrest the progression of unresectable or recurrent benign meningiomas of the skull base in some patients. It remains to be determined whether a controlled prospective clinical trial would be useful.

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Arachnoscopy: a special application of spinal intradural endoscopy

Uwe Max Mauer, Andreas Gottschalk, Ulrich Kunz, and Chris Schulz

Object

The microsurgical removal of obstructions to CSF flow is the treatment of choice in the surgical management of intradural arachnoid cysts. Cardiac-gated phase-contrast MR imaging is an effective tool for the primary diagnosis and localization of arachnoid cysts. Microsurgery, however, does not lend itself to assessments of further adhesions beyond the borders of the exposed area. The use of a thin endoscope allows surgeons to assess intraoperatively whether the exposure is wide enough.

Methods

Between 2006 and 2010, a single neurosurgeon performed 31 consecutive microsurgical procedures with endoscopic assistance in 28 patients with spinal arachnoid adhesions. A MurphyScope endoscope was used for this purpose. The CSF flow was studied before and after surgery in all patients by using phase-contrast MR imaging in the region of the craniocervical junction, the cervical spine, the thoracic spine, and the lumbar spine.

Results

In all 31 procedures, CSF flow obstructions were detected at the level identified by phase-contrast MR imaging. In 29 procedures, image quality was sufficient for an inspection of the adjacent subarachnoid space. In 6 cases, the surgeon detected further adhesions that obstructed CSF flow in the adjacent subarachnoid space that were not visualized with the microscope. In all cases, these adhesions were identified and removed during microsurgery.

Conclusions

Arachnoscopy is a helpful adjunct to microsurgery and can be performed safely and easily. It allows the surgeon to detect further adhesions in the subarachnoid space that would remain undetected by microscopy alone.

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Influence of low glucose supply on the regulation of gene expression by nucleus pulposus cells and their responsiveness to mechanical loading

Laboratory investigation

Christina Rinkler, Frank Heuer, Maria Teresa Pedro, Uwe Max Mauer, Anita Ignatius, and Cornelia Neidlinger-Wilke

Object

Environmental alterations resulting in a decrease in the nutrient supply have been associated with intervertebral disc (IVD) degeneration, particularly of the nucleus pulposus (NP). The goal of the present study was to examine the hypothesis that glucose deprivation alters the metabolism of NP cells and their responsiveness to mechanical loading. A possible interaction of glucose supply and hydrostatic pressure (HP) with gene expression by NP cells has not been investigated.

Methods

The influence of glucose supply (physiological concentration: 5 mM, reduction: 0 or 0.5 mM) and cyclic HP loading (2.5 MPa, 0.1 Hz, 30 minutes) on bovine and human NP cell matrix turnover was analyzed by quantitative real-time reverse transcriptase–polymerase chain reaction. Glucose-dependent effects on cell viability were determined by trypan blue exclusion. A glycosaminoglycan (GAG) assay was performed to determine nutritional effects on the protein level.

Results

Glucose reduction resulted in significant downregulations (p < 0.05) of aggrecan, collagen-I, and collagen-II gene expression by bovine NP cells. Exemplary human donors also displayed a similar trend for aggrecan and collagen-II, whereas matrix metalloproteinases (MMPs) tended to be upregulated under glucose deprivation. After HP loading, human NP cells showed individual upregulations of collagen-I and collagen-II expression, while MMP expression tended to be downregulated under glucose reduction relative to a normal glucose supply. Cell viability decreased with glucose deprivation. The GAG content was similar in all groups at Day 1, whereas at Day 3 there was a significant increase under physiological conditions.

Conclusions

Glucose deprivation strongly affected NP cell metabolism. The effects of an altered glucose supply on gene expression were more pronounced than the mechanically induced effects. Data in this study demonstrate that the glucose environment is more critical for disc cell metabolism than mechanical loads. In individual human donors, however, adequate mechanical stimuli might have a beneficial effect on matrix turnover during IVD degeneration.

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Standard and cardiac-gated phase-contrast magnetic resonance imaging in the clinical course of patients with Chiari malformation Type I

Uwe Max Mauer, Andreas Gottschalk, Carolin Mueller, Linda Weselek, Ulrich Kunz, and Chris Schulz

Object

The causal treatment of Chiari malformation Type I (CM-I) consists of removing the obstruction of CSF flow at the level of the foramen magnum. Cerebrospinal fluid flow can be visualized using dynamic phase-contrast MR imaging. Because there is only a paucity of studies evaluating CSF dynamics in the region of the spinal canal on the basis of preoperative and postoperative measurements, the authors investigated the clinical usefulness of cardiacgated phase-contrast MR imaging in patients with CM-I.

Methods

Ninety patients with CM-I underwent preoperative MR imaging of CSF pulsation. Syringomyelia was present in 59 patients and absent in 31 patients. Phase-contrast MR imaging of the entire CNS was used to investigate 22 patients with CM-I before surgery and after a mean postoperative period of 12 months (median 12 months, range 3–33 months). In addition to the dynamic studies, absolute flow velocities, the extension of the syrinx, and tonsillar descent were also measured.

Results

The changes in pulsation were highly significant in the region of the (enlarged) cistern (p = 0.0005). Maximum and minimum velocities (the pulsation amplitude) increased considerably in the region where the syrinx was largest in diameter. The changes of pulsation in these patients were significant in the subarachnoid space in all spinal segments but not in the syrinx itself and in the central canal.

Conclusions

The demonstration of CSF flow pulsation can contribute to assessments of surgical outcomes. The results presented here, however, raise doubts about current theories on the pathogenesis of syringomyelia.

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In-depth characterization of a long-term, resuscitated model of acute subdural hematoma–induced brain injury

Thomas Datzmann, Thomas Kapapa, Angelika Scheuerle, Oscar McCook, Tamara Merz, Sarah Unmuth, Andrea Hoffmann, René Mathieu, Simon Mayer, Uwe Max Mauer, Stefan Röhrer, Deniz Yilmazer-Hanke, Peter Möller, Benedikt Lukas Nussbaum, Enrico Calzia, Michael Gröger, Clair Hartmann, Peter Radermacher, and Martin Wepler

OBJECTIVE

Acute subdural hematoma (ASDH) is a leading entity in brain injury. Rodent models mostly lack standard intensive care, while large animal models frequently are only short term. Therefore, the authors developed a long-term, resuscitated porcine model of ASDH-induced brain injury and report their findings.

METHODS

Anesthetized, mechanically ventilated, and instrumented pigs with human-like coagulation underwent subdural injection of 20 mL of autologous blood and subsequent observation for 54 hours. Continuous bilateral multimodal brain monitoring (intracranial pressure [ICP], cerebral perfusion pressure [CPP], partial pressure of oxygen in brain tissue [PbtO2], and brain temperature) was combined with intermittent neurological assessment (veterinary modified Glasgow Coma Scale [MGCS]), microdialysis, and measurement of plasma protein S100β, GFAP, neuron-specific enolase [NSE], nitrite+nitrate, and isoprostanes. Fluid resuscitation and continuous intravenous norepinephrine were targeted to maintain CPP at pre-ASDH levels. Immediately postmortem, the brains were taken for macroscopic and histological evaluation, immunohistochemical analysis for nitrotyrosine formation, albumin extravasation, NADPH oxidase 2 (NOX2) and GFAP expression, and quantification of tissue mitochondrial respiration.

RESULTS

Nine of 11 pigs survived the complete observation period. While ICP significantly increased after ASDH induction, CPP, PbtO2, and the MGCS score remained unaffected. Blood S100β levels significantly fell over time, whereas GFAP, NSE, nitrite+nitrate, and isoprostane concentrations were unaltered. Immunohistochemistry showed nitrotyrosine formation, albumin extravasation, NOX2 expression, fibrillary astrogliosis, and microglial activation.

CONCLUSIONS

The authors describe a clinically relevant, long-term, resuscitated porcine model of ASDH-induced brain injury. Despite the morphological injury, maintaining CPP and PbtO2 prevented serious neurological dysfunction. This model is suitable for studying therapeutic interventions during hemorrhage-induced acute brain injury with standard brain-targeted intensive care.