Expression of different isoforms of nitric oxide synthase in experimentally denervated and reinnervated skeletal muscle.

Denervated muscle fibers express enhanced levels of stress and apoptosis-associated proteins and undergo apoptosis. In experimentally denervated and reinnervated rat facial muscle, we now evaluate changes in the expression patterns of different isoforms of nitric oxide synthase (NOS)-generating nitric oxide (NO), which mediates oxidative stress and apoptosis. Physiological expression of NOS corresponds to a constant sarcolemmal staining pattern for neuronal NOS (nNOS) and a patchy sarcolemmal and weak sarcoplasmic labeling for the endothelial NOS-isoform, with no expression for inducible NOS (iNOS). Denervated muscle displayed distinct downregulation of nNOS with preserved expression of dystrophin. Also, denervated and immediately reinnervated muscle fibers showed decreased expression of nNOS. However, muscle fibers reinnervated for 10 weeks revealed a restored physiological expression of nNOS. There were no changes in the expression of endothelial and inducible NOS. As NO is known to induce growth arrest and collapse of neuronal growth cones, downregulation of NOS may contribute to promotion of axonal regeneration by aiding formation of new endplates. NO is upregulated in reinnervated muscle fibers and thus prevents polyneural hyperinnervation by extrajunctional synapses. Furthermore, downregulation of NOS during denervation is compatible with the finding that low levels of NO contribute to apoptosis instead of necrosis in disease states of oxidative stress.

Recovery of original nerve supply after hypoglossal-facial anastomosis causes permanent motor hyperinnervation of the whisker-pad muscles in the rat.

Hypoglossal-facial anastomosis (HFA), used in humans for the treatment of facial palsy, was experimentally performed in adult female Wistar rats. The time course of facial reinnervation and the extent of the new motor nerve supply of the vibrissal muscles that develops after HFA were estimated by counting all motoneurons in the brainstem labeled by injection of horseradish peroxidase (HRP) into the whisker pad; muscle innervation by motor endplates was not studied. In untreated animals, HRP injection labels 1,254 +/- 54 (mean +/- S.D.; n = 6) motoneurons, localized exclusively in the lateral subdivision of the facial nucleus. Immediately following HFA, this number drops to zero. The first HRP-labeled motoneurons appear in the hypoglossal nucleus at 28 days postoperation (dpo) and at 56 dpo their number reaches 1,096 +/- 48. Unexpectedly, the facial nerve, whose proximal stump has been left as blind end during surgery, additionally sends axons to the facial periphery. This resprouting is first detected at 42 dpo with HRP-marked neurons throughout the facial nucleus lacking somatotopic organization. The number of these labeled neurons also rises with time, and at 56 dpo, a total of 1,797 +/- 142 facial and hypoglossal motoneurons, that is, 43% more motoneurons than in normal animals, supplies the whisker pad. This hyperinnervation, that is, the projection of more motoneurons into the target muscle than under normal conditions--further increases to 1,978 +/- 92 motoneurons at 224 dpo and may provide a new animal model for studying the competitive relationships between motoneurons in their search for peripheral targets.

Local application of granulocyte-macrophage colony stimulating factor (GM-CSF) for the treatment of oral mucositis.

The combination of radiation and chemotherapy administered for patients undergoing therapy for advanced head and neck neoplasms leads to a significant rise in toxic side-effects. Oral mucositis remains one of the most distressing factors leading to pain, impairment of oral nutrition, local and systemic infection and often cessation of the oncological treatment. The local and systemic administration of recombinant growth factors has revealed a potential benefit in the treatment of oral mucositis. Clinical data concerning the topical use of granulocyte-macrophage colony-stimulating-factor (GM-CSF) in the prevention and therapy of mucositis in patients undergoing radiochemotherapy for advanced cancer of the head and neck are presented in this paper. A prospective, randomised, open parallel-grouped, single centre study at a university hospital was performed. 35 patients with stage III and IV carcinomas of the head and neck were included. Statistical analysis concerning the degree of oral mucositis, the perception of pain, the incidence of secondary infections and the change in haematological parameters revealed no superiority of GM-CSF in comparison to conventional mouthwash between the two groups of patients. As a result, and faced with the tremendous costs of the regular use of a recombinant cytokine, we ended the clinical trial after 35 patients. The topical administration of GM-CSF to treat oral mucositis as a result of radiochemotherapy in patients suffering from head and neck cancer cannot be recommended.

Changes in eye blink responses following hypoglossal-facial anastomosis in the cat: evidence of adult mammal motoneuron unadaptability to new motor tasks.

Hypoglossal-facial anastomosis is used in humans to restore the activity of the mimic musculature following irrecoverable facial nerve lesions. As eyelid movement kinetics is very well known, we have used this experimental model in cats to follow the evolution of blink responses and the adaptability of hypoglossal motor pools to new motor tasks. Although the electromyographic activity of the orbicularis oculi muscle in response to corneal air puffs, flashes of light or electrical stimulation of the supraorbital nerve was not recovered in the seven months following this crossed anastomosis, reflex blinks were got back by the increased activity of the retractor bulbi and extraocular recti muscles. The lid of the anastomosed side oscillated in perfect synchronization with tongue movements during licking, while it was severely affected in its motor function during optokinetic stimulation because of the spontaneous appearance of tongue-related hypoglossal activity. Present results suggest that adult mammal motoneurons are unable to readapt their motor programs to the kinetic needs of new motor targets and that most of the functional recovery observed in the cat was achieved by the compensatory hyperactivity of motor systems not directly affected by the surgery.

Nimodipine-accelerated hypoglossal sprouting prevents the postoperative hyperinnervation of target muscles after hypo glossal-facial anastomosis in the rat.

Hypoglossal-facial anastomosis (HFA), used for the treatment of facial palsy, was performed in adult Wistar rats. For 7-224 days post operation (DPO), half of the animals were kept on standard laboratory food and half received food pellets containing 1000 ppm of the Ca2+ channel blocker nimodipine. The postoperative neurotization of facial muscles in these two groups was traced by comparing numbers of all retrogradely labeled neurons after injection of HRP into the whiskerpad muscles. In unoperated animals, injection of HRP labeled 1254 ± 54 neurons. Immediately after HFA, this number dropped to zero. The treatment with nimodipine yielded two beneficial effects. (1) In the early phase of regeneration (until 28 DPO), it accelerated the sprouting of hypoglossal axons into the facial periphery; (2) In the final phase, it suppressed the axonal sprouting from both, hypoglossal and facial stumps. In this way nimodipine fully prevented the postoperative hyperinnervation, i.e. the projection of more hypoglossal plus facial motoneurons to the whiskerpad muscles than under normal conditions.

Computer-assisted surgery in the frontal and maxillary sinus.

We report the intraoperative use of bent probes for 3-dimensional computer-assisted navigation in ENT surgery with the ISG Viewing Wand. Probe calibration is standardized and the new probes comply with the overall application accuracy of the navigation system. The bent probes permit an easy access to the remotest locations of the maxillary and the frontal sinus and are beneficial for application in paranasal sinus surgery. We present our clinical experiences with these probes.

Computer-aided surgery in the petrous bone.

OBJECTIVE: We demonstrate that computer-assisted frameless stereotactic navigation with the ISG/ELEKTA Viewing Wand system in the petrous bone is routinely possible with sufficient application accuracy. METHODS: High-resolution computed tomography imaging is done with a dedicated structure attached to the mouthpiece of the Vogele-Bale-Hohner (VBH) head holder, an integral part of our intraoperative patient fixation. The patient image registration can be reliably performed before surgery in an unsterile environment with the registration structure of the mouthpiece. For intraoperative navigation either the position-sensitive articulated arm or the optical three-dimensional digitizer of the ISG/ELEKTA system is used. RESULTS: In the operations of the petrous bone performed so far, i.e., mastoidectomy, cholesteatoma surgery, and lateral skull base revision surgery, the clinical value of three-dimensional navigation was clearly demonstrated with an application accuracy, constant throughout surgery, mostly limited only by the resolution of the computed tomography.

Three-dimensional image-guided endonasal surgery with a microdebrider.

We report the first intraoperative use of a microdebrider as a stereotactic three-dimensional (3D) navigation instrument in paranasal and frontobasal surgery. The microdebrider uses rotating blades and an integrated suction device for controlled removal of tissue under video-endoscopic view. The ISG Viewing Wand uses the patient's computed tomography/magnetic resonance (CT/MR) data and a 3D reconstruction thereof and a high-precision position-sensitive mechanical arm for intraoperative three-dimensional navigation. We have linked the microdebrider to the Viewing Wand to transform it into a continuously available intraoperative stereotactic localizing device. We discuss the problems related to this extension of the Viewing Wand and demonstrate the practical use in an exemplary polypectomy.

Minimally invasive head holder to improve the performance of frameless stereotactic surgery.

Frameless stereotactic procedures crucially depend on the firmness of immobilization. Once registered, shifting of the patient leads to inaccuracy, and the patient registration has to be realigned. To overcome the drawbacks of conventional invasive fixation for neurosurgery and the widely accepted fixation with surgical tape in ENT, the Vogele-Bale-Hohner (VBH) head holder has been developed. It permits rigid, noninvasive fixation of the head by using an individualized dental cast attached to the upper jaw by vacuum. Oral intubation is uncomplicated. In addition, a special registration device providing well defined reference points can be mounted to the mouthpiece. We report the first promising clinical applications of this device.

Experience with various 3-dimensional navigation systems in head and neck surgery.

OBJECTIVE: To evaluate the benefits and difficulties encountered when using various 3-dimensional (3-D) navigation systems in head and neck procedures. DESIGN: Five different navigation systems were used for preoperative planning and intraoperative 3-D navigation in procedures at the paranasal sinuses, the frontal and lateral skull bases, and the petrous bone. INTERVENTION: Intraoperative 3-D localizing systems (position-sensitive mechanical arms, infrared cameras, etc) demand reliable patient fixation on the operating table. We achieved this by developing a noninvasive head holder. Other systems allow patient movements by using magnetic digitizing technology (ARTMA System) and sophisticated programming. RESULT: Having surpassed an initial learning curve, we now achieve an accuracy of 1 to 2 mm regularly. Especially in paranasal and frontal basal surgery, all navigation systems used provide valuable positioning information during surgery. In particular for revision or tumor surgery, decisive benefits resulted from use of these systems: shorter overall operation time; safer manipulation near delicate structures; and reliable identification of the skull base even in patients with bleeding, scarring, or missing anatomical landmarks. CONCLUSIONS: We performed approximately 250 operations with different systems and introduced navigation at the lateral skull base and the petrous bone with mechanical, optic, and magnetic digitizers. In these anatomical areas, navigation was used successfully; the technical challenge is greatest at the lateral skull base, however.

N-chlorotaurine, a novel endogenous antimicrobial agent: tolerability testing in a mouse model.

OBJECTIVE: To investigate the tolerability of N-chlorotaurine, a new antimicrobial agent, by application to the middle ear in a mouse model. METHODS: Five BALB/c mice were each injected through the tympanic membrane with 5 microL of 0.1%, 1.0%, and 10% N-chlorotaurine and compared with animals in which 0.9% isotonic sodium chloride solution, 0.2% gentamicin sulfate, and 0.25% trimethyltin chloride were instilled. Auditory brainstem responses to clicks were evaluated repeatedly between 4 and 75 days after injection, and histologic investigations of the inner ear were performed subsequently. Three additional groups of mice were injected with isotonic sodium chloride solution, 1.0% N-chlorotaurine, and 0.25% trimethyltin, and brainstem responses to tone bursts of 8, 16, and 32 kHz were tested. In addition, the middle ear was examined histologically. RESULTS: Mice treated with isotonic sodium chloride solution, 0.1% N-chlorotaurine, and 0.2% gentamicin sulfate did not show changes in response threshold. Treatment with 1.0% and 10% N-chlorotaurine caused a reversible increase in auditory brainstem response threshold by 20 dB 4 days after application because of local irritation around the perforation of the tympanic membrane. In contrast, 0.25% trimethyltin showed a permanent elevation of auditory brainstem response threshold of 10 to 15 dB and a scattered loss of outer hair cells predominantly in the apical turn. No alterations of the inner ear were observed in the other treatment groups. The mucous membrane of the middle ear remained unaffected in all test groups. CONCLUSION: Application of N-chlorotaurine to the middle ear is well tolerated without adverse effects and may be a useful new endogenous antimicrobial agent for local treatment of otologic infections.

Otorhinolaryngologic computer-assisted biopsies of the Iceman.

BACKGROUND: The Iceman is a prehistoric, completely preserved, 5300-year-old male human mummy. OBJECTIVE: To obtain the first biopsy specimens from inside the Iceman while meeting an extended standard of hygiene and following precise intraoperative guidance to the site of biopsy and keeping tissue damage to a minimum. DESIGN: Biopsy specimens from the nose, the maxillary sinus, and the larynx of the Iceman were obtained. Special caution had to be taken while performing the biopsies to not contaminate the Iceman with heavy metals or remnants of microorganisms. SUBJECT: The Iceman, a cadaver kept frozen in a glacier for 5300 years. The Iceman is in an excellent state of preservation and will allow fundamental histological, morphological, and molecular genetic insights into early man. INTERVENTION: The biopsies were planned and executed with the aid of Interventional Video Tomography, a system that guides the surgeon to the target area by combining live video with existing imaging modalities. The system does not need mechanical fixation of the subject (the Iceman) and is barely in physical contact with the subject; thus, it was the ideal tool for guiding the surgeon to the site of the biopsy samplings through a tiny canal into the nose, the maxillary sinus, and the larynx of the Iceman. RESULTS: We have obtained a number of tissue samples by precisely guided 3-dimensional navigation. Unnecessary tissue damage was avoided. CONCLUSIONS: Visual inspection of the extracted mucosa showed typical human cadaver tissue, despite its age, without clinical abnormalities. Currently, the samples are being investigated by various international scientific groups.

Three-dimensional navigation in otorhinolaryngological surgery with the viewing wand.

We report our experiences with the ISG Viewing Wand intraoperative 3-dimensional navigation device in endonasal endoscopic procedures of the paranasal sinuses, anterior skull base, and petrous bone. In the last 12 months we have routinely used the wand in 90 patients for treatment of polyposis nasi, for biopsies and removal of tumors in the nasal cavity and at the frontal skull base, for endocrine ophthalmopathy, and in 1 case for cholesteatoma. We present our computed tomography, magnetic resonance imaging, and clinical protocols that allow a precise routine use of the Viewing Wand. In all cases, the system was extremely helpful for intraoperative localization and helped to optimize surgery.

Dendritic cells in selected head and neck tumors.

Specimens from 17 head and neck tumor patients were immunohistochemically stained with monoclonal antibodies against HLA-DR, CD1a, RFD1, LAG, CD3, CD4, CD8, CD45RO, CD68, and cytokeratin to identify the nature and distribution of dendritic cells (DCs), T cells, and macrophages. Small numbers of DCs were present in all but 2 specimens. They were located between the tumor cells and in the stroma, especially in areas of inflammatory cell infiltration. Variable numbers of T lymphocytes (cytotoxic and memory type) occurred in the same locations. Numerous macrophages were found in the epithelium, in the stroma, and in the vicinity of tumor cells. The presence of DCs in head and neck tumors indicates that the organism has activated the immune surveillance system and is trying to present tumor antigens. Considering the sparsity of DCs in the malignant tissues, the T cell response can be only limited.

The hypoglossal-facial anastomosis as model of neuronal plasticity in the rat.

Hypoglossal-facial cross anastomosis (HFA) causes regeneration with change of function, as the axotomized hypoglossal motoneurons sprout into the facial plexus and reinnervate the mimic musculature. Following HFA, hypoglossal-hypoglossal single anastomosis (HHA) and resection of 8-10 mm peripheral hypoglossal nerve in 190 female adult Wistar rats, we compared the axon reactions in the hypoglossal nucleus during 1) regeneration with change of function, 2) regeneration with restoration of original function and 3) degeneration of the nucleus. Following postoperative survival times of 1-16 weeks we estimated the volume of the hypoglossal nucleus and counted the number of hypoglossal neurons with the physical disector on both sides of the brainstem. Additional sections of the same animals were reacted with anti-synaptophysin, anti-GFAP and the isolectin Griffonia simplicifolia I-B4 (GSA I-B4) as cytochemical markers for presynaptic boutons, activated astroglia and microglia. After HHA and HFA all hypoglossal neurons survive and the volume of the hypoglossal nucleus remains constant. Resection of the hypoglossal nerve leads to the loss of one third of the hypoglossal neurons and of one third of the volume of the hypoglossal nucleus within 16 weeks post operation. Hypoglossal-facial anastomosis and hypoglossal-hypoglossal anastomosis differ in postoperative swelling of the hypoglossal nucleus, microglia and astroglia activation and the duration of synaptic stripping. All differences are limited to the acute growth phase during regeneration. It is concluded that hypoglossal-facial anastomosis provides more stimulation and facilitates faster recovery of the hypoglossal nucleus than does hypoglossal-hypoglossal anastomosis.

3D image-guided surgery on the example of the 5,300-year-old Innsbruck Iceman.

Interventional Video Tomography (IVT) is regularly used for computer-assisted 3D navigation in ear-, nose, throat, and head & neck surgery in our clinic. We present the technology and its application to collect biopsies of a 5,300 year old, completely conserved male cadaver, the Iceman. IVT links intraoperative live video with medical imaging data sets, realizing real-time surgical guidance in the live video and/or in the medical images. The IVT data contain the video images and the spatial sensor information; this has a large potential for documentation, training, teaching, and telepresence. IVT allowed us to sample the Iceman's mucosa by the minimally invasive endoscopic approach of the maxillary sinus, the nasal cavity, and the larynx, minimizing tissue damage. Visual inspection of the sinuses and the mucosa revealed the typical mucosa of a fresh cadaver, albeit originating from the stone-age.

Activated and non-activated eosinophils in patients with chronic rhinosinusitis.

Nasal polyps develop out of an oedematous swelling of the mucous membrane, which is probably a localized mediator-dependent reaction of the mucous membrane in the lamina propria. Among other things, eosinophil cationic protein (ECP) is released from activated eosinophils. In previous studies, ECP was considered as measuring the degree of allergic dermatological illnesses and therapy was given accordingly. A group of 54 patients with massive polyposis requiring functional endoscopic sinus surgery was examined. After surgery they were treated with local and systemic cortisone. Polypous tissue samples were collected and counted for the number and ratio of activated and non-activated eosinophils, and the serum titre of ECP was measured simultaneously using a fluoroimmunoassay (test kit, Kabi Pharmacia, Sweden). The aim of the study was to evaluate the activity of the disease and to gain hints for a specific therapy. The presence of these eosinophils was demonstrated by immunohistochemical methods, using EG1 antibodies against non-activated and EG2 antibodies against activated (i.e. secreted form of ECP) eosinophils. Depending on the duration of treatment with systemic and local corticosteroids, there was a considerable decrease in activated eosinophils and the level of serum ECP. Consequently, cortisone can be applied in the treatment of eosinophilic nasal polyps. As the number of activated eosinophils in the tissue is an indicator for the activity of the chronic inflammation it can be deduced from our study that local and/or systemic cortisone application successfully stops the growth of eosinophilic nasal polyps. The number and ratio of activated and non-activated eosinophils seem to be reliable indicators for the activity of chronic polyposis.

Isolated longitudinal rupture of the posterior tracheal wall following blunt neck trauma.

The authors report 3 female children (4, 5 and 12 years old) who suffered an isolated rupture of the posterior tracheal wall (membranous part) following a minimal blunt trauma of the neck. Such tracheal ruptures often cause a mediastinal and a cutaneous thoraco-cervical emphysema, and can also be combined with a pneumothorax. The following diagnostic steps are necessary: X-ray and CT of the chest, tracheo-bronchoscopy and esophagoscopy. The most important examination is the tracheo-bronchoscopy to visualize especially the posterior wall of the trachea. Proper treatment of an isolated rupture of the posterior tracheal wall requires knowledge about the injury mechanisms. The decision concerning conservative treatment or a surgical intervention is discussed. In our 3 patients we chose the conservative approach for the following reasons: 1) The lesions of the posterior tracheal wall were relatively small (1 cm, 1.5 cm, 3 cm) and showed a good adaptation of the wound margins. 2) No cases showed an associated injury of the esophageal wall. All of our patients had an uneventful recovery, the lesion healed within 10 to 14 days, and follow-up showed no late complications.

A full 3D-navigation system in a suitcase.

OBJECTIVE: To reduce the impact of contemporary 3D-navigation systems on the environment of typical otorhinolaryngologic operating rooms, we demonstrate that a transfer of navigation software to modern high-power notebook computers is feasible and results in a practicable way to provide positional information to a surgeon intraoperatively. MATERIALS AND METHODS: The ARTMA Virtual Patient System has been implemented on a Macintosh PowerBook G3 and, in connection with the Polhemus FASTRAK digitizer, provides intraoperative positional information during endoscopic endonasal surgery. RESULTS: Satisfactory intraoperative navigation has been realized in two- and three-dimensional medical image data sets (i.e., X-ray, ultrasound images, CT, and MR) and live video. CONCLUSIONS: This proof-of-concept study demonstrates that acceptable ergonomics and excellent performance of the system can be achieved with contemporary high-end notebook computers.

VBH head holder to improve frameless stereotactic brachytherapy of cranial tumors.

Precise target localization is essential for brachytherapy. We have adapted the VBH (Vogele-Bale-Hohner) head holder (Wellhoefer Dosimetry, Schwarzenbruck, Germany), originally developed at the University of Innsbruck, for frameless stereotactic surgery, for use in brachytherapy of cranial tumors. The VBH head holder allows for rigid, noninvasive head fixation by means of an individualized upper dental cast. Registration rods, rigidly attached to the dental cast, provide stable external points of reference. The dental cast is sucked against the upper palate by vacuum, and then the fixated patient is scanned. During simulation, the targeting device can be positioned with respect to the virtual patient using the ISG Viewing Wand. Following simulation, the real patient is repositioned under vacuum control, the targeting device repositioned as well, and the actual brachytherapy initiated. The VBH head holder is well tolerated by patients and simple to use, and various studies have confirmed submillimeter accuracy. The modified head holder in combination with a new targeting device allows for precise and well-planned insertion of hollow needles into a tumor using frameless stereotactic systems as well as being compatible for uses in other fields.