Horst Kokemueller

Prefabrication of vascularized bioartificial bone grafts in vivo for segmental mandibular reconstruction: experimental pilot study in sheep and first clinical application

The key elements for bioartificial bone formation in 3D matrices are large numbers of osteogenic cells and supplies of oxygen and nutrition. Vascularization becomes more important with the increasing size and complexity of seeded scaffolds required for clinical application in reconstructive craniomaxillofacial surgery. Prefabrication of vascularized bioartificial bone grafts in vivo might be an alternative to in vitro tissue engineering techniques. Two cylindrical beta-TCP-scaffolds (25 mm long) were intraoperatively filled with autogenous bone marrow from the iliac crest for cell loading and implanted into the latissimus dorsi muscle in 12 sheep. To determine the effect of axial perfusion, one scaffold in each sheep was surgically supplied with a central vascular bundle. Sheep were killed 3 months after surgery. Histomorphometric analysis showed autogenous bone marrow from the iliac crest was an effective source of osteogenic cells and growth factors, inducing considerable ectopic bone growth in all implanted scaffolds. Bone growth, ceramic resorption and angiogenesis increased significantly with axial perfusion. The results encourage the application of prefabricated bioartificial bone for segmental mandibular reconstruction in man. In clinical practice, vascularized bioartificial bone grafts could change the principles of bone transplantation with minimal donor site morbidity and no shape or volume limitations.

Computer-assisted therapy in orbital and mid-facial reconstructions.

Management of orbital and mid‐facial fractures requires a thorough ophthalmic evaluation and precise imaging. A principle goal of therapy is to anatomically reduce fracture segments and to restore a normal orbital volume as soon as possible. Diagnostic advances such as new surgical and imaging techniques have dramatically improved both the functional and aesthetic outcome of reconstructions.

Computer-assisted navigation in craniomaxillofacial tumors.

Surgical procedures in the head and neck region require a detailed knowledge of this regions complex anatomy. Anatomic changes due to tumor growth present special challenges for the surgeon. In addition to the clinical examination, which is still of fundamental importance, imaging procedures such as computer-aided surgical navigation technology are currently being used in the preoperative, intraoperative, and postoperative assessments of anatomic changes. For purposes of analysis, we have analyzed the application of navigation technology into 2 categories: 1) minimally invasive procedure and biopsy; and 2) resection of extensive tumors and reconstruction after tumor surgery. Navigation can make tumor surgery more reliable by specifying correct safety margins, protecting vital structures, and facilitating the reconstruction process.

Speech and Swallowing Impairment After Treatment for Oral and Oropharyngeal Cancer

OBJECTIVES To assess the prevalence of speech and swallowing impairment after radical surgery for oral and oropharyngeal cancer from the patients viewpoint and to examine the association of these functional alterations with selected clinical characteristics regarding patients, tumors, and oncologic treatment. DESIGN Cross-sectional, multicenter study using a self-administered questionnaire. SETTING Forty-three hospitals in Germany, Switzerland, and Austria. PATIENTS A total of 3894 questionnaires about rehabilitation problems after treatment for oral and oropharyngeal squamous cell carcinoma were sent to patients. Of these, 1652 were filled out and returned, and 1334 (80.8%) met the inclusion criteria. MAIN OUTCOME MEASURES Morbidity associated with treatment of oral and oropharyngeal cancer. RESULTS Speech problems were reported by 851 patients (63.8%), and swallowing problems were reported by 1006 patients (75.4%). The variables that presented a significant association with speech and swallowing impairment were sex, tumor location, pTNM stages, stage of tumor, treatment modality, and reconstruction type. CONCLUSIONS This survey, based on patient perception, suggests that those who undergo radiotherapy associated with the surgical removal of a tumor, have late-stage tumors (III-IV), or have tumors located in the floor of the mouth should be informed of the greater risk of persistent severe speech and swallowing problems.

Pre-operative planning for mandibular reconstruction - A full digital planning workflow resulting in a patient specific reconstruction

ObjectivesReconstruction of large mandiblular defects following ablative oncologic surgery could be done by using vascularized bone transfer or, more often, primarily with simultaneous or delayed bone grafting, using load bearing reconstruction plates. Bending of these reconstruction plates is typically directed along the outer contour of the original mandible. Simultaneously or in a second operation vascularized or non-vascularized bone is fixed to the reconstruction plate. However, the prosthodontic-driven backward planning to ease bony reconstruction of the mandible in terms of dental rehabilitation using implant-retained overdentures might be an eligible solution. The purpose of this work was to develop, establish and clinically evaluate a novel 3D planning procedure for mandibular reconstruction.Materials and methodsThree patients with tumors involving the mandible, which included squamous cell carcinoma in the floor of the mouth and keratocystic odontogenic tumor, were treated surgically by hemimandibulectomy.ResultsIn primary alloplastic mandible reconstruction, shape and size of the reconstruction plate could be predefined and prebent prior to surgery.Clinical relevanceThis study provides modern treatment strategies for mandibular reconstruction.

Complex Midfacial Reconstruction: A Combined Technique of Computer-Assisted Surgery and Microvascular Tissue Transfer

The human midface is a complex anatomic region. The maxilla is the structural support between the skull base and the occlusal plane, resisting the forces of mastication, anchoring the dentition, separating the oral and nasal cavities, supporting the globe, and supporting the face and its mimetic musculature. 1 The midface region dominates our outward appearance, which is unique to each individual, and its esthetic restoration after loss of the maxilla is of major importance for quality of life. Destruction of the midface may result from trauma, infectious or malignant

Endoscope-assisted transoral reduction and internal fixation versus closed treatment of mandibular condylar process fractures--a prospective double-center study.

PURPOSE The aim of this international AO-study was to compare the functional outcome after open versus closed treatment of mandibular condylar neck fractures. PATIENTS AND METHODS A prospective comparative study with two follow-ups (FU) at 8-12 weeks and 1 year was undertaken in two clinics, which exclusively privileged either surgical or conservative treatment due to different therapeutic agendas. Patients from clinic 1 (ENDO group) received endoscope-assisted transoral open reduction and internal fixation, whereas patients from clinic 2 (CONS group) were treated conservatively without surgery. Patients with unilateral condylar neck fractures showing one or more of the following conditions were included: displacement of the condyle with an inclination >30° and/or severe functional impairment such as malocclusion or open bite, with or without dislocation of the condylar fragment; severe pain upon palpation or movement, and/or vertical shortening of the ascending ramus. High or intracapsular condylar neck fractures were excluded. RESULTS 75 patients (44 CONS and 31 ENDO patients) with condylar neck fractures were included in this study. The Asymmetric Helkimo Dysfunction Score (A-HDS) was slightly lower in the CONS group than in the ENDO group at the 8-12-week FU, corresponding to better function on the short-term. At the 1-year FU, however, there were slightly better values in the ENDO group. For the Clinical Dysfunction Index (Di) and the Anamnestic Dysfunction Index (Ai), CONS patients had a better outcome than ENDO patients at the 8-12 week FU, ie, a higher proportion of ENDO patients had severe symptoms due to the operative trauma. Yet these symptoms improved by one year, finishing with a significant higher proportion of symptom-free patients in the ENDO group. In addition, these patients had better values for the Index for Occlusion and Articulation Disturbance (Oi) at both FU examinations, ie, the proportion of patients without any occlusal disturbances was significantly higher in the ENDO group. On average, the duration of postoperative maxillo-mandibular fixation (MMF) was 3 times longer for the CONS group than for the ENDO group (33 vs. 11 days). CONCLUSION Both treatment options may yield acceptable results for displaced condylar neck fractures. Especially in patients with severe malocclusion directly after trauma, however, endoscope-assisted transoral open reduction and fixation seems to be the appropriate treatment for prevention of occlusal disturbances during FU.

The Hannover experience: Surgical treatment of tongue cancer - A clinical retrospective evaluation over a 30 years period

ObjectivesIn this retrospective study, we present a clinical review of our experience with tongue cancer in order to obtain valid criteria for therapeutic decision-making.Materials and methodsBetween 1980 and 2009, a total of 341 patients with squamous cell carcinoma of the tongue were treated at our Department. The average follow-up was 5.2 years. 309 patients received surgical treatment, which was combined in nearly 10% with neoadjuvant and in nearly 20% with postoperative radio(chemo)therapy. 32 patients were excluded from surgery and received primary radiation.ResultsLocal and regional failure occurred in 23.9% and 20.4%, leading to a total failure rate of 37.2% after an average duration of 1,6 years. N-Status, extracapsular spread and clear margins were identified as the dominant factors for survival, which was calculated with 54.5% after 5 years.ConclusionsWe recommend categorical bilateral neck dissection in order to reliably remove occult lymph node metastases. Adjuvant treatment modalities should be applied more frequently in controlled clinical trials and should generally be implemented in cases with unclear margins and lymphatic spread.Clinical relevanceThis study provides new treatment strategies for primary tumour disease and for tumour recurrence.

Influence of Different Types of Guns, Projectiles, and Propellants on Patterns of Injury to the Viscerocranium

PURPOSE Gunshot injuries to the oral and craniomaxillofacial region vary with the type of gun used. Computed tomography (CT) is the standard diagnostic tool for assessing tissue damage in patients with gunshot injuries. Cone-beam computed tomography (CBCT) is a new imaging technique that has recently become available for clinical diagnosis. The objective of this study was to characterize injury patterns with a focus on gun types and identify the imaging modality that is best suited to assessing injuries caused by different gun types. PATIENTS AND METHODS We present the cases of 14 patients who sustained gunshot injuries to the viscerocranium during the past 10 years. The injuries were caused by 8 basic combinations of handguns or long guns with soft lead core projectiles, partial or full metal-jacketed bullets, and different propellants. Diagnosis was based on clinical and radiological findings (including CT and CBCT). RESULTS We found a direct correlation between the gun/projectile combination on the one hand and the diameter of the wound track, tissue contamination, and tissue destruction on the other. Entrance and exit wounds are indicative of certain gun/projectile combinations. High-density projectiles cause severe artifacts in CT, unlike CBCT, making it difficult to evaluate anatomic structures in close proximity to the projectile. CONCLUSIONS Every gun/projectile combination is associated with a typical pattern of injury. Even in the absence of the offending projectile, it is thus possible to narrow down the likely gun and/or projectile. In the diagnostic imaging of injuries caused by high-density projectiles, CBCT is more suitable than CT.

Forty Sandwich Osteotomies in Atrophic Mandibles: A Retrospective Study

PURPOSE The aim of the present retrospective study was to assess the suitability of segmental mandibular sandwich osteotomy combined with an interpositional autograft to meet the dimensional requirements of preimplant bone augmentation in cases of a severely atrophic mandible. PATIENTS AND METHODS A total of 27 consecutive patients (6 men and 21 women) were included in the present study. The amount of bone gain was calculated using digital volume tomography before surgery and 3 months after bone augmentation. RESULTS The postoperative course was uneventful for 18 patients. Temporary sensory disturbances were observed in 6 patients, with complete recovery after 3 to 12 weeks. Dehiscence of soft tissue closure occurred in 3 patients. The mean vertical gain was 3.41 mm (range 0.3 to 12). The mean horizontal gain was 3.08 mm (range 0.2 to 8.5). A total of 88 implants were placed in 40 surgical sites at 12 weeks after bone reconstruction. CONCLUSION Segmental mandibular sandwich osteotomy is a suitable augmentation procedure in the mandible for the atrophic alveolar ridge and provides adequate height and transversal bone augmentation.