Philipp Pohlenz

Outcome and complications of 540 microvascular free flaps: the Hamburg experience.

The aim of this study was to retrospectively analyze surgical outcome and complications of 540 free flap procedures performed at the Department of Oral and Maxillofacial Surgery of the University Medical Center Hamburg-Eppendorf during 1987–2005. A total of 532 patients were reconstructed with 540 flaps: 32% were latissimus dorsi flaps, 23% were radial forearm flaps, 21% were iliac crest flaps, 10% were fibula flaps, 6% were jejunal flaps, and 8% were other flaps. Thrombosis of one of the vessels and hematoma were the most frequent causes of failure in microvascular free tissue transfer. A total free flap failure occurred in 34 (6.2%) and a partial flap failure in 42 (7.7%) patients. The most reliable flap in regard to survival was the radial forearm flap. The present study confirms that free flaps are extremely reliable in achieving successful reconstruction of the head and neck.

Intraoperative Cone-Beam Computed Tomography in Oral and Maxillofacial Surgery Using a C-Arm Prototype : First Clinical Experiences After Treatment of Zygomaticomaxillary Complex Fractures

PURPOSE To describe the first clinical applications of intraoperative cone-beam computed tomography with an integrated flat-panel detector in oral and maxillofacial surgery after surgical treatment of zygomaticomaxillary complex fractures PATIENTS AND METHODS Nine cone-beam computed tomography datasets of patients with zygomaticomaxillary complex fractures were intraoperatively acquired using a mobile isocentric C-arm (PowerMobil; Siemens Medical Solutions, Erlangen, Germany), including a flat-panel detector. Datasets based on 400, 200, and 100 fluoroscopic images were performed with different tube currents (4.6 mA, 3.3 mA, 2.3 mA, 1.2 mA, and 0.5 mA) and a current tube voltage of 100 kV. Postprocessing resulted in 15 different datasets available for comparison with corresponding preoperative computed tomography datasets. Four oral and maxillofacial surgeons and 2 experienced radiologists evaluated each dataset regarding noise, transition, and the delimitation of landmarks. RESULTS All examinations were successfully performed. Reconstructed datasets showed high-resolution images of all midfacial osseous structures in near-computed tomography quality. Regarding high-contrast structures, detailed analyses of datasets acquired in this study suggest that the parameters 400 projections, 1.2 mA, and 100 kV are sufficient. In terms of soft-tissue visualization, a higher level of mA seems preferable. CONCLUSIONS The tested prototype predicts a new era in cone-beam computed tomography imaging. The integration of a flat-panel detector will overcome the limitations of current available systems. The size of the field of view is increased allowing regularly the visualization of the whole facial skeleton. Particularly in cases of open reduction of unilateral fractures, the assessment of symmetry is of clinical value.

Virtual dental surgery as a new educational tool in dental school

PURPOSE The virtual environment of the Voxel-Man simulator that was originally designed for virtual surgical procedures of the middle ear has been adapted to intraoral procedures. To assess application of the simulator to dentistry, virtual apicectomies were chosen as the pilot-test model. METHODS A group of 53 dental students provided their impressions after virtual simulation of apicectomies in the Voxel-Man simulator. RESULTS Fifty-one of the 53 students recommended the virtual simulation as an additional modality in dental education. The students indicated that the force feedback (e.g. simulation of haptic pressure), spatial 3D perception, and image resolution of the simulator were sufficient for virtual training of dental surgical procedures. CONCLUSION The feedback from dental students involved in this pilot-test has encouraged our interdisciplinary group to continue further development of the simulator with the goal of creating new training strategies in dental and medical education.

Clinical follow-up examination of surgically treated fractures of the condylar process using the transparotid approach.

PURPOSE The surgical approaches for the open treatment of condylar process fractures have been controversial. In our study, we evaluated the morbidity of the transparotid approach during 2 years of follow-up. PATIENTS AND METHODS A total of 48 patients with condylar process Class II and IV fractures according to classification of Spiessl and Schroll, were included in the present study. Of the 48 patients, 16 were female and 32 male. The patient age range was 16 to 79 years (average 36.52). All patients were treated using the transparotid approach, with rigid internal fixation using miniplates. Follow-up examinations were performed for a minimum of 6.5 months and a maximum of 25 months (average 12.16) after surgical treatment. At the follow-up examination, the patients completed the Mandibular Function Impairment Questionnaire, and the examiner completed the Helkimo index. X-rays taken before, directly after, and 6 months after surgery were compared. RESULTS None of our patients had problems with wound healing; 2 patients developed a fistula of the parotid gland; and 4 patients developed palsy of the facial nerve that was completely reversible after 6 weeks. The results of the Mandibular Function Impairment Questionnaire and the Helkimo index revealed only a few subjective and objective problems after 6 months. CONCLUSIONS The transparotid approach to condylar process fractures is most appropriate for strongly displaced Class II fractures. Especially for very old patients with dementia, for whom maxillomandibular fixation is contraindicated, this approach is very appropriate. Another benefit to this type of patient is the short operating time, with an average of 45 minutes.

Major Mandibular Surgical Procedures as an Indication for Intraoperative Imaging

PURPOSE This study investigated 3-dimensional (3D) imaging with intraoperative cone beam computed tomography (CBCT) in major mandibular reconstruction procedures. PATIENTS AND METHODS The study group was comprised of 125 patients (83 males, 42 females) admitted for surgical treatment of the mandible. The patients ranged in age from 3 months to 91 years (average age, 40.72 +/- 22.843 years). Surgical procedures of the mandible were subdivided into repair of body fractures (17 patients), angle fractures (21 patients), condylar fractures (14 patients), and multiple fractures (30 patient). In addition, the study group included 21 patients undergoing orthognatic surgery and 22 undergoing reconstructive surgery on the mandible. Intraoperatively, 3D images were generated with a mobile CBCT scanner (Arcadis Orbic 3D; Siemens Medical Solutions, Erlangen, Germany). RESULTS During open reduction of mandibular fractures, not all fracture sites can be readily exposed for direct visual control. For example, the lingual cortical bone of the mandible is difficult to assess intraoperatively. This structure and others can be effectively visualized using the 3D mode of CBCT. Furthermore, screw placement can be evaluated, specifically in insertions near the alveolar nerve. The intraoperative acquisition of the data sets is uncomplicated, and the image quality is sufficient to allow evaluation of the postoperative result in all cases. CONCLUSION Intraoperative CBCT has proven to be a reliable imaging technique for providing visual control during major mandibular procedures.

Intraoral osteotomies using piezosurgery for distraction in an infant with Pierre–Robin sequence

Airway management in infants with Pierre Robin sequence (PRS) is often challenging. Advancement of the tongue base using mandibular distraction in neonates can avoid tracheotomy and is increasingly propagated. The osteotomies can be performed via intra- and extraoral approaches. Nowadays, for precise bone cutting, piezosurgical devices have been introduced in maxillofacial surgery, which we used for osteotomies via the intraoral approach in the 7-week-old patient presented in this study. Instead of a preoperative CT scan, a 3D data set was generated preoperatively in the operating theatre using a 3D C-arm system. After bilateral transcutaneous pin placement and osteotomies, a second 3D data set was acquired. Primary and secondary reconstructions clearly visualized the patient’s bone despite the low level of ossification in newborns and the presence of a large amount of metal implants. In view of the low level of radiation exposure going along with the 3D C-arm imaging, a follow-up examination after removal of the distractors was performed. With this report of a 7-week-old female infant with the diagnosis of PRS, we want to extend the surgical and diagnostic armamentarium for the treatment of infants with PRS.

Clinical indication for intraoperative 3D imaging during open reduction of fractures of the neck and head of the mandibular condyle.

PURPOSE This study aimed to evaluate the use of intraoperative cone-beam computed tomography (CBCT) in monitoring the results of repositioning and osteosynthesis of condylar process and head (capitulum) fractures of the mandible to see if CBCT is beneficial for these patients. PATIENTS AND METHODS Sixty patients (22 females and 38 males, age range 16-79 years, average 36.5 years) with condylar process and head fractures according to the classification of Spiessl and Schroll were treated during the study period. Thirty-four of the 60 patients received a CBCT scan immediately after surgical treatment under aseptic conditions. RESULTS In all 34 cases, intraoperative CBCT provided high-quality imaging of the condylar process in all three planes. In four patients (11.8%), unsatisfactory reposition or unexpected complications were detected which could immediately be corrected with a surgical revision. CONCLUSION Intraoperative use of CBCT enables optimization of the surgical outcome for fractures of the condylar process and head of the mandible, reduces postoperative complications, and spares patients from repeated intervention. In addition, intraoperative CBCT enables safer treatment with minimally invasive approaches.

The use of navigation (BrainLAB Vector vision2) and intraoperative 3D imaging system (Siemens Arcadis Orbic 3D) in the treatment of gunshot wounds of the maxillofacial region

PurposeGunshot wounds are a rare occurance during times of peace. The removal of projectiles is recommended; in some cases, however, this is a controversy. The reproduction of a projectile image can be difficult if it is not adjacent to an anatomical landmark. Therefore, navigation systems give the surgeon continuous real-time orientation intraoperatively. The aim of this study was to report our experiences for image-guided removal of projectiles and the resulting intra- and postoperative complications.Patients and methodsWe investigated 50 patients retrospectively; 32 had image-guided surgical removal of projectiles in the oral and maxillofacial region. Eighteen had surgical removal of projectiles without navigation assistance.ResultsThere was a significant correlation (p = 0.0136) between the navigated surgery vs. not-navigated surgery and complicaton rate, including major bleeding (n = 4 vs. n = 1, 8% vs. 2%), soft tissue infections (n = 7 vs. n = 2, 14% vs. 4%), and nerval damage (n = 2 vs. n = 0, 4% vs. 0%; p = 0.038) and between the operating time and postoperative complications. A high tendency between operating time and navigated surgery (p = 0.1103) was shown. When using navigation system, we could reduce operating time.ConclusionIn conclusion, there is a significant correlation between reduced intra- and postoperative complications, including wound infections, nerval damage, and major bleeding, and the appropriate use of a navigation system. In all these cases, we could present reduced operating time. Cone-beam computed tomography plays an important role in detecting projectiles or metallic foreign bodies intraoperatively.

Technical and surgical aspects of the sphenopalatine ganglion (SPG) microstimulator insertion procedure

Cluster headache (CH) is a debilitating, severe form of headache. A novel non-systemic therapy has been developed that produces therapeutic electrical stimulation to the sphenopalatine ganglion (SPG). A transoral surgical technique for inserting the Pulsante SPG Microstimulator into the pterygopalatine fossa (PPF) is presented herein. Technical aspects include detailed descriptions of the preoperative planning using computed tomography or cone beam computed tomography scans for presurgical digital microstimulator insertion into the patient-specific anatomy and intraoperative verification of microstimulator placement. Surgical aspects include techniques to insert the microstimulator into the proper midface location atraumatically. During the Pathway CH-1 and Pathway R-1 studies, 99 CH patients received an SPG microstimulator. Ninety-six had a microstimulator placed within the PPF during their initial procedure. Perioperative surgical sequelae included sensory disturbances, pain, and swelling. Follow-up procedures included placement of a second microstimulator on the opposite side (n=2), adjustment of the microstimulator lead location (n=13), re-placement after initial unsuccessful placement (n=1), and removal (n=5). This SPG microstimulator insertion procedure has sequelae comparable to other oral cavity procedures including tooth extractions, sinus surgery, and dental implant placement. Twenty-five of 29 subjects (86%) completing a self-assessment questionnaire indicated that the surgical effects were tolerable and 90% would make the same decision again.

Immunohistochemical analysis of p16 expression, HPV infection and its prognostic utility in oral squamous cell carcinoma.

OBJECTIVES Functional inactivation of p16 is an early and frequent event in the carcinogenesis of tumours of the head and neck region. However, the prognostic relevance of p16 protein expression for these tumours has been controversial. This study aims to examine immunohistochemical expression of p16 and HP virus in a large number of oral carcinomas, and possible correlation with clinical features of the tumours and survival of the patients. METHODS Two tissue microarrays composed of 222 oral carcinomas and 427 squamous cell carcinomas of the head and neck region were used for this study. Sections were stained immunohistochemically (anti-p16), and PCR analysis (HPV status) was carried out. Correlation of p16 expression/HPV status with features of tumours and with survival of the patients was analysed by means of Chi-squared test and using Kaplan-Meier analysis, respectively. RESULTS p16 expression was found immunohistochemically in 74% of tumours, but was not significantly correlated with features of the tumours, but recurrence-free survival of the patients (P = 0.009) if located predominantly nuclear. On the other hand neither intensity of p16 expression (P = 0.41) nor HPV status (P = 0.82) had any effect on these two aspects. CONCLUSION Immunohistochemical expression of p16 alone provides a limited tool for diagnosis and prognosis of carcinomas of the head and neck region. Immunohistochemical analysis of p16 depending on its intracellular location might serve as a surrogate marker for HPV infection.