BACKGROUND: Intraoperative three-dimensional (3D) navigation systems determine spatial positions and visualize them in radiological data sets. Usually, data from 3-D computed tomography (CT) are used. We have successfully implemented "augmented reality" in routine clinical practice by superimposing positional data and guiding and ancillary structures on the live endoscopic video of the operating site. Thus, optimal access paths and anatomical structures such as the a. carotis interna or the n. opticus can be displayed. METHODS AND RESULTS: With modern telecommunication, any two locations can be connected for intraoperative consultations with a remote expert, and 3D navigation is an ideal complement. We have successfully tested telephone, ISDN, Ethernet, and ATM technology intraoperatively and find that the ARTMA system provides well-developed technology. CONCLUSIONS: Stereotactic telepresence can provide essential aid in difficult surgical procedures, and the ARTMA Knowledge-Guided Surgery system will contribute further to the optimization of computer-assisted surgery.

Endoscopes↗

PubMed2001

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.

Animals↗

PubMed2001

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.

Humans↗

PubMed2001

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.

Adult↗

PubMed2000

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.

Endoscopes↗

PubMed2000

[Computer-aided 3D-navigation systems. Survey and location determination].

3D-navigation systems have only recently been introduced into the surgical field. Since then they have gained increasing importance not only in ENT surgery but also in neurosurgery, orthopedic surgery, maxillo-facial surgery, radiology and radiotherapy. Following a brief historical introduction this article reviews existing navigation technologies, in terms of indication, practicability, accuracy, forensic and financial aspects. The selection of the navigation system is strongly influenced by the planned procedure (endoscopic, microscopic, open approach). According to our experience most of these systems provide useful support intraoperatively. The clinical application accuracy regularly lies in the range of 1-2 mm.

Diagnostic Imaging↗

PubMed2000

[Value of a nutrition score in patients with advanced carcinomas in the area of the head and neck].

BACKGROUND AND OBJECTIVE: Patients with advanced head and neck cancer often suffer from malnutrition even before the start of therapy. Hence, the demand for nutritional support increases particularly before and during radiochemotherapy. Though nutritional therapy has been shown to substantially improve individual outcome, neither the criteria for patient candidacy nor the indications for therapeutic intervention have been established. We performed a retrospective analysis to determine the indications for nutritional support and < 0 evaluate the benefits of measures actually taken against malnutrition before and during radiochemotherapy as well as perioperatively. PATIENTS/METHODS: Data taken from a prospective study for the evaluation of oral mucositis during radiochemotherapy was analysed retrospectively. To calculate the indication for nutritional support, a nutritional scoring system (Hackl) was employed for the first time, which contained biochemical and anthropometric parameters as well as the period of starvation. The results were then compared to a nutritional support program implemented by the subjective examinations of the attending physician. RESULTS: Changes in body weight and body mass index (BMI) remained the most impressive parameters. Catabolic metabolism developed preoperatively and a significant loss of whole-body protein followed surgical therapy. Clinically, the results of the nutritional score correlated with the observation of malnutrition. Furthermore, our findings suggest that nutritional therapy was commonly delayed until late in the clinical course. CONCLUSION: The results indicate the necessity of objective and reproducible diagnosis and control of malnutrition. The scoring system used may provide a useful and yet simple tool for assessing individual indications for timely nutritional support.

Adult↗

PubMed2000

Head and neck tumors: fractionated frameless stereotactic interstitial brachytherapy-initial experience.

The authors used a frameless stereotactic navigation system, the Vogele-Bale-Hohner head holder, and a targeting device to reproducibly position brachytherapy needles for fractionated interstitial brachytherapy in 12 patients with inoperable cancers of the head and neck. In all cases, deviations of the needle relative to the planned position were within 1-15 mm depending on the location of the tumor.

Brachytherapy↗

PubMed2000

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.

Antibodies, Monoclonal↗

PubMed1999

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.

Child↗

PubMed1999

The influence of the tonsillar gag on efficacy of seal, anatomic position, airway patency, and airway protection with the flexible laryngeal mask airway: a randomized, cross-over study of fresh adult cadavers.

UNLABELLED: We conducted a randomized, controlled, cross-over cadaver study to test the hypothesis that the efficacy of seal for ventilation and airway protection, anatomic position, and airway patency with the flexible laryngeal mask airway (FLMA) are altered by the application of a Boyle Davis (B-D) gag. We also determined the airway sealing pressure (ASP) at which the FLMA prevents aspiration when large volumes of fluid are placed above the cuff. We studied 20 adult cadavers (6-24 h postmortem). Efficacy of seal for ventilation and airway protection, anatomic position, and airway patency were determined with and without a B-D gag (two blade sizes: 8 and 10 cm) for the size 3, 4, and 5 FLMA in random order. Efficacy of seal for ventilation was determined by measuring the ASP at an intracuff pressure of 60 cm H2O. Efficacy of seal for airway protection was determined by flooding the mouth with 55-135 mL of water, reducing intracuff pressure until aspiration was detected fiberoptically and measuring ASP at this intracuff pressure. Anatomic position and airway patency were determined with a fiberoptic scope at an intracuff pressure of 60 cm H2O. In addition, in vivo compliance and ASP for the FLMA were measured in 10 cadavers and 10 paralyzed, anesthetized patients. Efficacy of seal for ventilation and airway protection, anatomic position, and airway patency did not change with the application of a gag for any mask size. The mean (range) ASP at which aspiration occurred when large volumes of fluid were placed above the cuff was 11 (7-15) cm H2O. The ASP for ventilation was always higher than the ASP for airway protection (P<0.0001). The FLMA had similar in vivo compliance and ASP in cadavers and anesthetized patients. We conclude that efficacy of seal for ventilation and airway protection, anatomic position and airway patency for the FLMA are unaffected by the application of a B-D gag in adults. ASP should be >15 cm H2O if there is a maximal risk of aspiration from above the cuff. IMPLICATIONS: The flexible laryngeal mask airway forms an effective seal for ventilation and protection of the airway that is unaffected by the application of a mouth gag that provides surgical access to the oropharynx. The efficacy of the seal should be >15 cm H2O if there is a maximal risk of aspiration from above the cuff.

Aged↗