PubMed Health⌕ Search

Biomedical subjects

N C Gellrich

Publications and source records attributed to N C Gellrich.

At least 19 recordsLinked to original sources
PubMed2006

Inferior alveolar nerve transposition--an in vitro comparison between piezosurgery and conventional bur use.

An in vitro comparison between a new ultrasound-based piezoelectric device and a conventional bur was performed for lateralization or transposition of the inferior alveolar nerve to evaluate the effects on soft and hard tissue. Transposition of the inferior alveolar nerve was performed in the cadaver mandibles of 10 sheep: the left nerve was uncovered with a saline-cooled diamond-coated spherical bur (2000 rpm), and the right nerve was uncovered with the piezoelectric device mounted with a spherical diamond tip. The surface, the zone of bone defect, and the nerve were examined by light microscopy and laser microscopy. Bone treated with the rotary bur showed significantly smoother surfaces and shallower defect zones (50 microm) in comparison with the piezoelectric device (150 microm). Lesions of the epineurium and an increased amount of bone particles were found in the lesions prepared with the piezoelectric device. In vitro preparation with the piezoelectric device was more invasive to the bone than was a conventional diamond bur. Touching the inferior alveolar nerve resulted in roughening of the epineurium without affecting deeper structures. The degree of injury was lower than when using the conventional rotary bur.

Animals↗
PubMed2005

A congenital teratoma with a cleft palate: report of a case.

Teratomas are benign tumors containing cells from ectodermal, mesodermal and endodermal layers. They occur in about 1 in every 4000 births and most commonly in the sacrococcygeal region, followed by the ovaries. Congenital epignathus teratomas are rare embryological neoplasms localised in the region of head and neck. An epignathus is found in approximately 1:35,000 to 1:200,000 live births. This accounts for 2-9% of all teratomas. Size and location of the neoplasm in the oronasopharynx is variable. Teratomas are partly undiagnosed at the time of birth. They may exist with an intracranial extension or as small polyps. Large epignathi can lead to difficult management during and after birth. The case of a newborn girl with a combination of an epignathus and a cleft palate is described. The epignathus presented as a huge mass extending out of the mouth of the infant girl. On the day of birth debulking of the extraoral portion of the tumor, followed by intraoral exstirpation, was performed. The results of the histologic examination indicated a congenital epignathus. Six months later a recurrence was found.

Cleft Palate↗
PubMed2002

[Extraoral and intraoral endoscopically assisted management of collum fractures].

AIM OF THE STUDY: Using limited extraoral and transoral incisions for an endoscopically assisted open reduction of condylar mandible fractures, the risk of facial nerve damage and extensive visible scars can be reduced. PATIENTS AND METHODS: The endoscopically assisted treatment of 17 consecutive patients with fractures of the condyle was performed from April 1998 to December 1999. Of the 17 patients, 14 had additional mandibular fractures, and 11 of the condylar fractures were dislocated. Of the 17 patients, 9 were treated by submandibular and 8 by transoral approach. Adequate anatomic reduction was achieved by the submandibular and transoral approaches using an endoscopically assisted technique. APPROACHES: In four patients angulated drills and screwdrivers facilitated the transoral treatment of condylar fractures. Transbuccal stab incisions and the use of trocars were not needed in these four patients. The transoral approach proved to be a reliable surgical approach for fractures of the mandibular condyle even when dislocation with lateral override was present. The extraoral approach was used for severely dislocated fractures such as fractures with medial override or comminution.

Adult↗
PubMed2002

[Color duplex ultrasound in monitoring vascularized fibula transplants].

BACKGROUND: For the successful management of vascularized free fibular bone grafts, the early detection of vascular complications is important. When vascular complications are suspected without a reliable monitoring of the graft perfusion, revision surgery often proved to be unnecessary. Color duplex sonography for the postoperative monitoring of free fibular bone grafts without a skin island is demonstrated. MATERIAL AND METHODS: The quantitative and qualitative monitoring of the perfusion of microvascular anastomosis and the transplanted tissues using color duplex sonography with a 7.5-Mhz scanner (Elegra, Siemens, Germany) for the postoperative monitoring of 12 free fibular bone grafts was performed. Using color duplex sonography, the perfusion of the vascular pedicle and the free fibular bone grafts was demonstrated in all 12 free fibular bone grafts. In three patients vascular complications and failure of the bone grafts were suspected due to postoperative complications next to free fibular bone grafts such as abscess formation, wound dehiscence, and disturbances of wound healing. Using color duplex sonography, adequate perfusion of the vascular pedicle and the transplanted tissue was demonstrated and therefore revision surgery not indicated. DISCUSSION: Color duplex sonography is a reliable, noninvasive, and inexpensive method for the postoperative monitoring of free fibular bone grafts.

Ameloblastoma↗
PubMed2002

Endoscopy-assisted open treatment of condylar fractures of the mandible: extraoral vs intraoral approach.

By using an endoscopy assisted extraoral and transoral approach for open reduction of condylar mandible fractures with limited incisions, the risk of facial nerve damage and extensive visible scars can be reduced. The endoscopy-assisted treatment of 17 consecutive patients with fractures of the condyle was performed from April 1998 to December 1999. Of the 17 patients, 13 presented with additional mandibular fractures. Nine of the 17 patients were treated by a submandibular approach and eight by a transoral approach. Adequate anatomic reduction was achieved by the submandibular and transoral approach using an endoscopy-assisted technique. The transoral approach proved to be a reliable surgical approach for fractures of the mandibular condyle, even when dislocation with lateral override was present. In four patients, angulated drills and screwdrivers facilitated the transoral treatment of condylar fractures. Transbuccal stab incisions and the use of trochars were not needed in these four patients. The extraoral approach was indicated for severely dislocated fractures such as fractures with medial override or comminution.

Adult↗
PubMed2001

Morphological and functional analysis of an incomplete CNS fiber tract lesion: graded crush of the rat optic nerve.

Fiber tract lesions in the central nervous system (CNS) often induce delayed retrograde neuronal degeneration, a phenomenon that represents an important therapeutic challenge in clinical neurotraumatology. In the present study, we report an in vivo trauma model of graded axonal lesion of CNS neurons. Controlled by a newtonmeter device, we induced retrograde degeneration of adult rat retinal ganglion cells (RGCs) by graded crush of the optic nerve. The extent of secondary RGC death increased linearly with the applied crush force. Moreover, visually evoked potentials were used to characterize the consequences of controlled optic nerve lesion on the functional integrity of the visual projection. The presented model of fiber tract lesion closely resembles the clinical conditions of traumatic brain injury and could prove useful to screen for neuroprotective drugs based on both a morphological and functional read-out.

Animals↗
PubMed2001

[Optimized hemodilution with hydroxyethyl starch. A blood saving method in malocclusion operations].

UNLABELLED: OPTIMIZED HEMODILUTION: To avoid blood transfusions, the method of optimized hemodilution (OHD) was developed. OHD consists of preoperative hypervolemic hemodilution with 500 ml hydroxyethyl starch (HES) and consecutive volume replacement with HES in the case of intraoperative intravasal fluid loss. This study verifies the efficacy of OHD. RESULTS: Mono- and bimaxillary operations (n = 213) performed between January 1995 and May 1999 were evaluated retrospectively with respect to reduction of blood transfusions due to application of OHD. The average blood loss in the OHD group (n = 127) was 593 ml, and no blood transfusion was required. In contrast, the control group (n = 86) showed an average blood loss of 738 ml, and 15% of these patients (n = 13) required transfusion of a total of 18 blood units. Based on our results, provision of autologous blood is only necessary for patients who do not receive OHD. The costs of fluid replacement and transfusion are increased by a factor of 5.7 when OHD is not used. DISCUSSION: OHD should be preferably used in cases of elective surgery on patients with good cardiopulmonary health. It is an easy to handle infusion regimen, which does not require additional monitoring, has no risk of infection, and results in a significant cost reduction.

Blood Loss, Surgical↗
PubMed2001

Versatility and donor site morbidity of the lateral upper arm flap in intraoral reconstruction.

OBJECTIVE: The lateral upper arm flap is not widely used yet for intraoral defect reconstruction. Investigation of its morphologic and functional outcome was the objective of this study. STUDY DESIGN: The morphologic and functional results of recipient (swallowing, flap survival, dehiscence of margins, cutaneous fistulas, intraoral hairs) and donor sites (wound healing, scar width and length, sensory and motor disturbance) (n = 44) were checked clinically. Postoperative swallowing was investigated via videofluorography (n = 11). RESULTS: The lateral upper arm flap showed low donor site morbidity, primary closure was achieved in all but one case. Sensory deficit at the proximal forearm (n = 27) occurred without any case of compromise of radial nerve function. Videofluorography allows for objective evaluation of swallowing function. CONCLUSIONS: The lateral upper arm flap is the reconstruction of first choice for intraoral defects due to its low donor site morbidity.

Adult↗
PubMed2001

Prelaminating the fascial radial forearm flap by using tissue-engineered mucosa: improvement of donor and recipient sites.

In reconstructive surgery, prelamination of free flaps using split-thickness skin is an established technique to avoid the creation of a considerable defect at the donor site, for example, in the case of a radial forearm flap. For oral and maxillofacial surgery, this technique is less than optimal for the recipient site because the transferred skin is inadequate to form a lining in the oral cavity. To create mucosa-lined free flaps, prelamination using pieces of split-thickness mucosa has been performed. However, the availability of donor sites for harvesting mucosa is limited. The present study combines a tissue-engineering technique with free flap surgery to create mucosa-lined flaps with the intention of improving the tissue quality at the recipient site and decreasing donor-site morbidity. On five patients undergoing resection of squamous cell carcinoma of the oral cavity, the radial forearm flap was prelaminated with a tissue-engineered mucosa graft to reconstruct intraoral defects. Using 10 x 5 mm biopsies of healthy mucosa, keratinocytes were cultured for 12 days and seeded onto collagen membranes (4.5 x 9 cm). After 3 days, the mucosal keratinocyte collagen membrane was implanted subcutaneously at the left or right lower forearm to prelaminate the fascial radial forearm flap. One week later, resection of the squamous cell carcinoma was performed, and the free fascial radial forearm flap pre- laminated with tissue-engineered mucosa was transplanted into the defect and was microvascularly anastomosed. Resection defects up to a size of 5 x 8 cm were covered. In four patients, the graft healed without complications. In one patient, an abscess developed in the resection cavity without jeopardizing the flap. During the postoperative healing period, the membrane detached and a vulnerable pale-pink, glassy hyperproliferative wound surface was observed. This surface developed into normal-appearing healthy mucosa after 3 to 4 weeks. In the postoperative follow-up period, such functions as mouth opening and closing and speech attested to the success of the tissue-engineering technique for flap prelamination.

Aged↗
PubMed2000

Indications for computer-assisted treatment of cranio-maxillofacial tumors.

OBJECTIVE: Ablative tumor surgery requires detailed planning using computed tomography (CT) or magnetic resonance imaging (MRI). Reconstruction following tumor resection is dependent on reliable information for choosing the correct type and volume of grafts and predicting the outcome. This study evaluates the benefit of and the indications for computer-assisted surgery in the treatment of cranio-maxillofacial tumors. MATERIALS AND METHODS: Based on a CT or MRI data set, the STN Navigation System (Stryker-Leibinger) was used for preoperative planning, intraoperative navigation, and postoperative control of radical tumor resection and primary and secondary reconstruction. Tumor resection was preoperatively planned and intraoperatively navigated. Preoperatively, the required soft and hard tissue were measured using the mirrored data set of the unaffected side of the facial skeleton; the size and location of the graft were chosen virtually. Intraoperatively, contours of transplanted tissues were navigated in accordance with the preoperatively simulated reconstructive result. RESULTS: Computer-assisted treatment was successfully completed in all cases of radical tumor resection, and safety margins outlined preoperatively could be precisely controlled during tumor resection. Reconstruction was designed and performed exactly as virtually planned. CONCLUSIONS: Image-guided treatment improves preoperative planning by visualization of the individual anatomy and the intended reconstructive outcome, and by objectivation of the effect of adjuvant chemo-/radiotherapy. Intraoperative navigation makes radical tumor surgery more reliable by showing the determined safety margins, preserving vital structures, and guiding reconstruction to preplanned objectives.

Adolescent↗
PubMed2000

[Computer-assisted insertion of zygomatic implants (Brånemark system) after extensive tumor surgery].

Installation of fixtures for prosthetic reconstruction of the upper jaw in patients with extensive bone and soft tissue defects is still a challenge. The new fixture developed by Brånemark System achieves immediate prosthetic reconstruction by anchoring implants in the zygomatic bone to offer sufficient support without bone grafts. The dimension of these zygomatic fixtures and the complex anatomy due to previous surgical procedures demand specific treatment for a precise and safe insertion of the implants. On the basis of an axial spiral CT data set, the STN navigation system (Stryker-Leibinger/Zeiss) was used for preoperative planning and intraoperative control of the insertion of zygomatic fixtures after subtotal maxillectomy. Computer-assisted insertion of zygomatic fixtures was successfully completed. The implants could be positioned precisely as preoperatively planned. The use of zygomatic fixtures after ablative tumor surgery with resection of the maxillary bone provides immediate prosthetic reconstruction without additional bone grafting. Computer-assisted insertion of these implants improves preoperative planning and facilitates clinical procedure.

Computer-Aided Design↗
PubMed2000

[3D SPECT reconstruction - a diagnostic method in oral and maxillofacial surgery].

Computer-aided three-dimensional (3D) reconstruction of conventional (99m)Tc-DPD SPECT data was used for basic investigations of different disease entities of the orofacial area, with the aim of improving primary diagnosis and, in selected cases such as microvascular bone reconstruction, for a more comprehensive control after therapy. So far, the new 3D technique has been applied in 49 patients with different indications based on commonly acquired sets of data without any further hazard for the patients. In comparison to conventional planar scintigrams, the advantage of this sophisticated technique is a higher image contrast and a clear-cut signal of the investigated bone areas without any superimposing effects. Therefore, the anatomical description of the process is better, which is particularly important in cases of osteomyelitis and after microvascular reconstruction of skull bone defects. In addition, the follow-up investigations can assess treatment results far better and outcome predictions are much more reliable. A higher sensitivity and specificity in cases of squamous cell carcinoma as regards bone infiltration could not be achieved so far. In summary, computer-aided 3D reconstruction of conventionally acquired (99m)Tc-DPD-SPECT data represents a significant improvement in radionuclide imaging technique, providing a much better diagnostic interpretation of selected disease entities in the oral and maxillofacial area.

Adult↗
PubMed2000

[Comparative in vitro studies of self-boring and self-tapping screws. Histomorphological and physical-technical studies of bone layers].

Self-drilling screws are gaining increasing importance in maxillofacial surgery. This study assesses which screw design, self-drilling or self-tapping, is best suited to various locations of the human skull. With regard to different areas in the human midface, mandible, and cranium, the thickness of cortical bone varies as well as the relative proportion of cortical to cancellous bone. Criteria used to judge the success of screws were minimal insertion torque and minimum temperature, maximum pullout strength, and minimum deformation and destruction of the bone. To mimic the variations in anatomical conditions, 1-mm and 3-mm-thick cortical bone specimens and cancellous bone blocks were prepared. Eight screws of three types (self-tapping, self-drilling/self-tapping, conically shaped self-drilling) were inserted into the different bone specimens. Torque and temperature were measured during the insertion procedure. Subsequently, the screws were carefully removed and the specimens were processed for histological evaluation. The same insertion protocol was used to test the pull-out strength of the screws. The conically shaped screw showed best results in cancellous bone for all parameters. The self-tapping screw with a pilot hole performed best in thick cortical bone and the self-drilling/self-tapping screw performed better than did the others in thin bone. The results suggest the three screw designs to be optimal for different locations of the human skull. This project provides the data for a planned in vivo study that will evaluate the long-term influence of deformation and temperature on stability and osseointegration of the screws.

Animals↗
PubMed2000

The lateral upper arm free flap for intraoral reconstruction.

Twenty-three consecutive patients who were reconstructed with a lateral upper arm free flap (LUFF) were examined especially concerning functional and morphological results at the recipient and donor sites. There were 22 intraoral and one upper oesophageal reconstruction after radical laryngectomy. The LUFF rendered good functional and esthetic results except for one case of complete and one case of incomplete flap necrosis due to vascular insufficiency of the supplying vessel of the neck. There was some sensory deficit of the donor site (n=10), but no radial nerve injury or conspicuous scarring. Recipient site dehiscence occurred in two cases and a temporary orocervical fistula was seen in one case. Oral function was maintained due to the thin and pliable flap. Excellent flap adaptation to the adjacent tissue was obtained in eight cases of complete loss of lingual attached gingiva in the molar region and in four cases of loss of buccal attached gingiva. The success and functional results of LUFF were comparable to the results of 14 cases in which radial forearm free flaps (RFFF) were used. Although the length of the pedicle and the diameter of the vessels in LUFF are smaller than in RFFF, neither pedicle length nor vessel diameter proved to be a problem. Extent of scarring and risk of vascular compromise proved to be less as compared to RFFF. LUFF is, therefore, the flap of choice for intraoral soft tissue reconstruction and it is advised to reserve RFFF for cases in which LUFF fails.

Adult↗
PubMed1999

[Complex reconstruction of the area of the maxilla and mid-face after radical tumor surgery].

The esthetic and functional restoration of facial defects is always a daunting challenge. The advent of free vascularized tissue transfers in combination with oral implants enables the surgeon to attain a high level of flexibility in the treatment of such defects. Due to its anatomical properties, the osteocutaneous scapula flap qualifies to a high degree for reconstruction purposes in the midfacial area. From July 1990 to February 1997, reconstruction of complex facial defects after oncologic surgery was performed in 17 patients using free vascularized tissue transfer. In four cases, a free scapula flap was used. Advantages and disadvantages of this technique are illustrated in these patients. Complete oral rehabilitation requires bony continuity of the jaws and stable dentition. To attain this goal, additional grafting procedures are required in most cases when insertion of oral implants is planned. As for the soft tissues, the problem of measuring the amount of tissue needed often leads to an overcorrection, requiring several debulking procedures.

Adult↗
PubMed1999

[Therapy refractory idiopathic thrombocytopenia. Contraindication for dental surgery interventions].

Hemorrhagic diathesis represents a high risk for oral surgery. In clinical practice various kinds of diathetic diseases are seen that are of plasmatic, vascular, thrombocytic and hypertensive origin. Usually these patients will be primarily referred to the hospital as high-risk cases. Therefore, a broad spectrum of diagnostic and therapeutic interdisciplinary methods are available, so that as a rule it is possible to obtain a clear picture of the severity of the bleeding tendency. We represent a case of a 58-year-old woman who had decayed teeth with chronic periodontal and periapical lesions, who could not be treated by oral surgery because of refractory idiopathic thrombocytopenic purpura (ITP) with 1000 platelets/microliters. The patient's history showed that various hematologic concepts had been tried, including splenectomy, but all had failed entirely. After therapy with steroids, immunosuppressive and cytostatic agents, and even after administering immunoglobulins and substitution with platelets, the count did not increase; thus, an absolute contraindication for all kinds of surgery was declared. This rare example indicates that unmanagable bleeding diseases still exist that should be known by dentists and oral surgeons to prevent making deleterious therapeutic decisions.

Contraindications↗
PubMed1999

[Controversies and current status of therapy of optic nerve damage in craniofacial traumatology and surgery].

In craniomaxillofacial traumatology, surgical oncology and craniomaxillofacial reconstruction, a surgeon's aim may interfere with the prechiasmatic visual pathway. Precise concepts and therapeutic strategies are mandatory to detect and deal with anterior visual pathway disorders. In order to develop these strategies, knowledge of the pathomechanisms of potential optic nerve trauma, primary radiological investigations, and further diagnostic measures are important. Due to the difficulties in neuroophthalmological testing of visual pathway functioning in severely injured patients or even during craniomaxillofacial reconstructions, we established flash-evoked visual potentials (VEP) and the electroretinogram (ERG) as reliable electrophysiological methods to gather specific information as to whether the visual pathway function is intact, even if pathological, but still present or absent. Case reports show that subjectively or objectively confirmed unilateral amaurosis does not necessarily mean irreversible vision loss. The electrophysiological evaluation together with multiplanar computer tomography (CT) are important for the immediate identification of optic nerve trauma. The results of this evaluation will provide the diagnostic information on whether surgical intervention and/or conservative therapy is required to prevent secondary optic nerve damage. The conservative therapy of choice for the treatment of traumatic optic nerve lesions is the methylprednisolone-megadosis regimen (30 mg Urbason/kg bodyweight i.v. and 5.4 mg/kg bodyweight/h i.v. for the following 47 h). Surgical therapy involves decompression of the orbital compartment in case of retrobulbar hematoma or decompression of the intracanalicular part of the optic nerve in the traumatized optic canal or posterior orbit as confirmed by CT. Prospective analysis of our trauma patients and the international literature on traumatic optic nerve lesions show that the time factor in when to start therapy has been greatly underestimated. To fulfill modern treatment concepts in craniomaxillofacial surgery, sound diagnostic and therapeutic knowledge on the maintenance of visual pathway function is required.

Adolescent↗