Alexander Schramm

Navigational maxillofacial surgery using virtual models.

Ablative tumor surgery and orbital and midface reconstruction, as much as orthognathic surgery, requires detailed planning using computed tomography (CT) or magnetic resonance imaging (MRI). These techniques also allow simulation of complex surgeries preoperatively. Proper reconstruction depends on reliable information to choose the correct type of grafts and to predict the outcome. This study evaluates the benefit and indications of computer-assisted surgery in the treatment of 107 patients who underwent craniomaxillofacial surgery. Based on a CT or MRI data set, an optical navigation system was used for preoperative planning, intraoperative navigation, and postoperative control. Surgery could be preoperatively planned and intraoperatively navigated. Preoperatively, it required that soft and hard tissues were measured using the mirrored data set of the unaffected side; the size and location of the graft were chosen virtually. Intraoperatively contours of transplanted tissues were navigated to the preoperatively simulated reconstructive result. Computer-assisted treatment was successfully completed in all 107 cases. Preoperatively outlined safety margins could be exactly controlled during tumor resection. Reconstruction was designed and performed precisely as virtually planned. Image-guided treatment improves preoperative planning by visualizing the individual anatomy, outlining the intended reconstructive outcome, and by objectifying the effect of adjuvant therapy. Intraoperative navigation makes tumor and reconstructive surgery more reliable by showing the safety margins, saving vital structures, and leading the reconstruction to preoperatively planned objectives.

Intraoperative navigation assisted reconstruction of a maxillo-facial gunshot wound

IntroductionThis case report describes a suicidal gunshot wound to the head using a handgun (9u2009×u200919xa0mm). During mandibular penetration, the solid hollow point projectile (Aktion4) was deformed but did not fragment. The mandible, mid-face, orbit, and nasal complex were severely damaged. Here, the authors present, for the first time, a new approach for bilateral mid-facial fractures.Materials and methodsFor virtual reconstruction, a naso-orbito-ethmoidal complex of an unaffected skull (same age, sex, and ethnic group) was merged into the computed tomography (CT) data set. Based on this data set, a navigation assisted operation was performed.ConclusionThe favorable outcome leads us to recommend the technique of merging comparable CT data for reconstructive planning of bilateral mid-facial fractures.

Objektivierung von Therapieergebnissen in der Schädelbasischirurgie durch virtuelle Modellanalyse

BACKGROUNDnVirtual model analysis of patient head tracking allows for objectivity and the monitoring of therapeutic results of pathologies in the skull base region. The introduction of these models in clinical routine has been impaired by the extended time needed for the preparation of radiological data.nnnMETHODSnQuality control analysis was carried out for seven cases with different pathological findings in the skull base region in patients who had undergone virtual model analysis.nnnRESULTSnPreparation time of radiological data for the process of segmentation required, under optimal conditions, a minimum of 30 min. Virtual model analysis enables spatial visualization of regions of interest and adjacent anatomical structures. This improves case-specific pathoanatomical understanding as well as preoperative planning of surgical strategies.nnnCONCLUSIONSnVirtual model analysis improves the physicians spatial comprehension of localized pathological findings at the dysmorphic interface of bone and soft tissue across the skull base. Therefore, it seems to be an adequate tool for quality control analysis of therapeutic results after extended skull base surgery.ZusammenfassungHintergrundDie patientenkopfgetrackte virtuelle Modellanalyse erlaubt die Objektivierung und das Monitoring von Therapieergebnissen im Schädelbasisbereich. Lange Rechnerzeiten haben bislang eine Einführung in die klinische Routine verhindert.MethodenIn einer Qualitätssicherungsanalyse wurden die Patientendaten von 7xa0Patienten unterschiedlicher Pathologien im Schädelbasisbereich nach virtueller Modellanalyse ausgewertet.ErgebnisseDie Bearbeitungszeit für das Segmentieren interessierender anatomischer Strukturen betrug in unserer Auswertung im günstigsten Fall 30xa0min. Die virtuelle Modellanalyse erlaubt das räumliche Visualisieren interessierender Strukturen zu ihrer Umgebung und verbessert somit das fallbezogene pathologisch -anatomische Verständnis für die Therapieplanung.SchlussfolgerungenHinsichtlich der dysmorph verlaufenden Knochen-Weichteil-Grenzflächen im Schädelbasisbereich erlaubt die virtuelle Modellanalyse derartig lokalisierter Pathologien ein verbessertes räumliches Verständnis und eignet sich zur Qualitätssicherung von Therapieergebnissen.AbstractBackgroundVirtual model analysis of patient head tracking allows for objectivity and the monitoring of therapeutic results of pathologies in the skull base region. The introduction of these models in clinical routine has been impaired by the extended time needed for the preparation of radiological data.MethodsQuality control analysis was carried out for seven cases with different pathological findings in the skull base region in patients who had undergone virtual model analysis.ResultsPreparation time of radiological data for the process of segmentation required, under optimal conditions, a minimum of 30xa0min. Virtual model analysis enables spatial visualization of regions of interest and adjacent anatomical structures. This improves case-specific pathoanatomical understanding as well as preoperative planning of surgical strategies.ConclusionsVirtual model analysis improves the physician’s spatial comprehension of localized pathological findings at the dysmorphic interface of bone and soft tissue across the skull base. Therefore, it seems to be an adequate tool for quality control analysis of therapeutic results after extended skull base surgery.

Navigationsunterstützte tumorfokussierte Chirurgie bei Schädelbasismalignomen

ZusammenfassungHintergrundLokal fortgeschrittene frontale Schädelbasismalignome (T4-Stadium) haben eine ungünstige Prognose. Zum Erhalt der Lebensqualität sollte bei gleicher Prognose eine therapiebedingte Invalidisierung möglichst vermieden werden. Wegen der geringen Inzidenz liegen keine evidenzbasierten allgemeingültigen Therapiekonzepte vor.MethodenAls Fallbeschreibung wurden die Therapieergebnisse von 3xa0Patienten mit ausgedehnten frontalen Schädelbasismalignomen im T4-Stadium ausgewertet. Berücksichtigt wurden der klinische Verlauf sowie die gewählte Operationstechnik.ErgebnisseBei allen 3xa0Patienten wurde im Rahmen eines multimodalen Therapiekonzeptes eine neoadjuvante Hochdosis-Chemotherapie zur Tumorverkleinerung („Tumor-Downsizing“) durchgeführt. Der durch die Tumorremission atraumatisch erzeugte zusätzliche chirurgische Manipulationsraum unmittelbar an den Tumorgrenzen erlaubte ein navigiert kontrolliertes, unter endoskopischer oder mikroskopischer Sicht sicheres Resezieren des Tumors („targeted surgery“) über einen patientenschonenden Zugangsweg.FazitDie unmittelbare Nachbarschaft lokal progredient wachsender T4-Frontobasistumoren zum Frontalhirn oder anderen vitalen Strukturen schränkt die chirurgische Radikalität ein. Durch ein kontrolliertes Tumor-Downsizing lassen sich solche Tumoren u.xa0U. über patientenschonende, wenig traumatisierende Zugangswege mittels computerassistierter Chirurgie im Sinne einer „targeted surgery“ entfernen.AbstractBackgroundMultimodal strategies are required due to the poor prognosis for locally advanced frontal skull base tumors staged as T4. Therefore, a further increase in the degree of invalidity caused by therapy should be avoided, if possible, to preserve the quality of life. As the incidence of these tumors is low, there are no evidence-based, generally accepted therapeutic strategies.MethodsWe evaluated the clinical results of three patients with extended frontal skull base malignomas staged as T4 tumors. The clinical course as well as the surgical technique were analyzed.ResultsHigh dose neoadjuvant therapy for tumor downsizing was performed in all three patients within a multimodal therapy concept. The additional space for surgical manipulation close to the tumor borders, non-traumatically produced by tumor remission, permitted a safely navigated, controlled resection of the tumor under endoscopic or microscopic viewing using an approach associated with reduced trauma as “targeted surgery”.ConclusionsSurgical radicality is limited by the direct vicinity of locally progressive T4 tumors to the frontal brain and other vital structures. A controlled tumor downsizing allows the resection of such tumors using a minimally invasive approach assisted by instrumental navigation leading to less traumatization.