A correlation of the surgical anatomy of the dura to head and neck surgery

Head and neck surgery may be complicated by penetration of the dura resulting in meningitis, cerebrospinal rhinorrhoea, cerebral abscess or other intracranial complications. The strength of the dura mater both protects the brain and spinal cord and makes dura an ideal material for grafting (when needed). This study examines the thickness and histological composition of dura mater at various sites encountered in head and neck surgery. Dura was removed from eight specified locations in 14 adult cadavers. Microscopically, this dura was found to consist predominantly of collagen fibres, although the thickness of the dura varied between sites. Dura was significantly thinner in relation to the ethmoid sinus (P less than 0.01), tegmen (P less than 0.05) and sigmoid sinus (P less than 0.001), indicating its greater susceptibility to possible injury at these sites during surgery. The variety of its thickness also makes dura a more versatile homograft material than hitherto realised.     

Analysis of the dura involvement in cholesteatoma surgery

Objective

The involvement of the dura is a rare yet potentially life-threatening complication during cholesteatoma surgery. Thus, the knowledge about treatment and consequences of this issue is of great importance to every ear surgeon.

狗硬脑膜与阔筋膜承受拉力比较

目的比较狗阔筋膜和硬脑膜所能承受拉力的差异.方法使用XL-250A型拉力实验机分别测定同期、相同条件下取得的狗阔筋膜和硬脑膜所能承受的最大拉力.结果两种不同方向的阔筋膜的拉力强度无显著差别,阔筋膜与硬脑膜二者之间的拉力强度差别不显著,然而,二者之间每毫米所承受的拉力差别显著.结论用阔筋膜修复硬脑膜缺损足以支持脑组织.     

Head and neck anatomy and ultrasound correlation

Thorough knowledge of the complex anatomy of the head and neck is essential to understanding the ultrasonographic appearance of this region. The intimate familiarity with anatomic structures obtained by performing surgical procedures makes active radiographic imaging modalities like ultrasound especially suited for use by surgeons. An understanding of the normal sonographic appearance of head and neck structures is critical to recognizing abnormal pathology.     

Methods for simulation of surgical interventions in head and neck surgery]

Preoperative evaluation of the operating site is essential in planning surgical procedures. The relationship of pathology to adjacent tissues and vital anatomical structures needs to be analyzed to determine the intraoperative procedures required. For this the surgeon mentally simulates the procedure planned. For complicated conditions or reconstructive surgery in extensive bony defects, surgery can be simulated with three-dimensional reconstruction on either a monitor screen or on an individually manufactured plastic model of the patient. For this purpose different procedures for 3 D representation and manipulation of tomographic image data have been developed in our departments and the technique of stereolithography used experimentally to create custom-made plastic model of patients. A computerized video image manipulator was also developed for simulation of aesthetic plastic surgical procedures.     

Adaptation to surgery for head and neck cancer

We examined the postoperative adjustment of 45 patients who underwent surgery for cancers of the head and neck: 23 who had laryngeal cancer, 18 who had oral cavity/oropharyngeal cancers, and 4 who had cancers of other sites. Patients were assessed preoperatively, and at 3 months and 9 to 12 months postsurgery. Interviews and questionnaires were used to assess depression, body image, limitations, pain, financial problems, need for help at home, and social interaction. Results revealed that pain, fatigue, weakness, and loss of speech were major concerns. Pain and financial concerns were worst at 3 months and then improved. Physical limitations increased steadily with time. Depression was a major factor in patients with oral cavity and oropharyngeal cancers. Of note, patients who underwent postoperative radiation therapy had the most difficulty adapting to their illness and treatment, with persistent limitations in function and social isolation. The implications of these findings are discussed.     

A new head and neck surgical drain fixation technique

We describe a simple technique of drain fixation in head and neck surgery using a beaded 2/0 nylon suture and a 'clove hitch' to achieve a non-slip fixation to the drain.     

Endocrine responses to head and neck surgery in men

It has been well established that surgical stress leads to profound changes in endocrine function and metabolism. However, the endocrine response varies depending upon the type and the extent of surgery. As no data were available about the endocrine changes during and following major head and neck surgery, this study was performed. Plasma levels of adrenocorticotropin (ACTH), cortisol, thyroid-stimulating hormone (TSH), thyroxin (T4), triiodothyronine (T3), growth hormone (GH), prolactin (PRL), gonadotropins (LH and FSH), oestradiol and testosterone were determined in 17 patients one day before, immediately after, as well as 2 and 4 days after head and neck surgery. An increase in ACTH, cortisol, PRL and GH, and a decrease in plasma oestradiol and testosterone values occurred immediately after surgery. There was a slow fall in cortisol levels after surgery, but they remained elevated even on the fourth postoperative day, whereas GH values returned on the fourth day to the initial level. There were no changes in gonadotropins, TSH and T3, but T4 values were found to be increased on the second and fourth postoperative day. The prolonged cortisol stimulation which was not described by other researchers after other kinds of surgery might be caused by vagal stimulation during and/or after head and neck surgery. Increased needs after a major head and neck surgery could explain the increment of T4 values.     

Hypothermia during head and neck surgery

OBJECTIVE: To determine the predictors and incidence of hypothermia in patients undergoing head and neck surgery. STUDY DESIGN: Retrospective analysis. METHODS: Patients were either not warmed (n = 43) or actively warmed with forced-air warming (n = 25). Clinical variables that were assessed as predictors of core body temperature included age, body mass, duration of procedure, estimated blood loss, amount of intravenous fluids administered, and the use of forced-air warming. The incidence of severe intraoperative hypothermia and potential hypothermia-related complications was also examined. RESULTS: The study demonstrated that advanced age is a risk factor for hypothermia and decreased body mass is associated with lower final body temperatures in the groups of patients that was not warmed. After adjusting for differences in the ages and weights between the two groups, the mean core body temperature was found to be 0.4 degrees C lower in the patients who were not warmed. Severe intraoperative hypothermia occurred in 5 of 38 patients (11.6%) who were not warmed and 2 of 23 patients (8.0%) who were warmed. The complications associated with hypothermia included delayed time to extubation, the development of neck seromas, and flap dehiscence. CONCLUSIONS: Patients undergoing head and neck surgery are at risk for the development of intraoperative hypothermia and require careful temperature monitoring. Elderly patients and patients with low body mass are more prone to develop low intraoperative core body temperatures. Active warming with forced-air warmers should be considered for patients at risk for intraoperative hypothermia and for patients who develop hypothermia intraoperatively, to avoid hypothermia-related complications.     

Topographic anatomy of the external branch of the superior laryngeal nerve. Its importance in head and neck surgery

The authors have studied the anatomy of the external branch of the superior laryngeal nerve in its entirety on 40 fresh cadavers, and they have drawn the following conclusions: the nerve ramifies from the vagus immediately below the nodose ganglion or in the ganglion itself. The nerve splits into two branches approximately 1.5 cm below the ganglion nodosum. In four cases, both branches originated from the vagus itself. In one case, anastomosis of the external branch of the superior laryngeal nerve with the recurrent nerve was found. The external branch of the superior laryngeal nerve is not usually severed at supraglottic laryngectomy but the nerve is at risk during neck dissections, resection of Zenker's diverticula and thyroidectomy. An accurate knowledge of its course should reduce the incidence of injury to the branches of the superior laryngeal nerve during surgery.     

Risk factors for surgical wound infections in patients undergoing head and neck oncologic surgery

Risk factors for surgical wound infection are difficult to establish in head and neck surgery. Flap reconstruction, which correlates with tumour size and surgical procedure, appears to be the main risk factor. Attempts should be made by the surgical staff to improve surgical procedures in terms of duration of surgery and choice of the procedure. The intraoperative choice between primary closure and flap reconstruction should be studied further. More subtle risk factors may appear in studies of large groups of patients and/or if a distinction is drawn between early and late SWI.     

Navigation-supported surgery in the head and neck region

Few of the pioneering manufacturers who attempted to develop navigation systems have been able to establish themselves within the market long-term. The same applies to the technological basis of these systems which aid intraoperative anatomical orientation. The first few systems registered the mechanical displacement of the navigational instrument's axes. Optoelectronic and electromagnetic methods are now prevalent. In contrast to electromagnetic systems, the "line of sight" between the camera system, the reference markers placed on the patient's head and the navigation instruments must remain unobstructed during the navigation process when using electrooptical navigation systems. Whereas, in the past, only preoperative CT scans were used for navigation, the integration of MRI and sonography--whose images can now be fused with each other and with those provided by other intraoperative imaging techniques such as fluoroscopy and endosonography--has become increasingly popular. Navigation systems require input of information about spatial conditions. This is carried out via procedures of registration and referencing, by means of which the relative position of reference markers at the head of the patient is correlated with the image data. The equipment is calibrated in the same way. Headsets, headbands and bone-anchored adapters are available for the fixation of the markers in the patient's head. Whereas the use of a headband or headset requires considerably less time, bone-anchored referencing increases the precision of the navigation system. The surgeon must be able to manage the different methods. In order to reduce the time required for preoperative preparation and to enhance the handling of the navigation processor for the surgeon, it is essential to have a clear menu. The surgeon is able to plan the steps involved in the surgery using the processor, define the access to the surgical site and control the surgery intraoperatively. Preoperative segmentation of functionally and clinically relevant structures enables minimally invasive surgery to be carried out, such as procedures with the aim of acquiring biopsy tissue and the search for foreign bodies. Following the technical development of the systems, the manufacturers are endeavouring to simplify their handling in close coordination with the users. The next step has to be the clinical evaluation of the navigation systems in accordance with the EBM standard, in order to establish this assistive method as routine clinical practice while applying meaningful medical criteria.     

A new implant system in head and neck surgery]

Defects in the head and neck region following extensive tumor removal are sometimes difficult to reconstruct by local or free flaps. An epithesis is a recommended alternative in defects of the ear, the nose or the orbital region. Nevertheless problems may arise in the appropriate fixation of the epithesis. With the intermobile-cylinder-implant-system (IMZ), the epithesis is firmly fixed by means of osseointegration of the implants and an abutment in the area of the defect. The various steps of the operation and clinical applications are presented.