Jan-Michaél Hirsch
Uppsala University
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Publication
Featured researches published by Jan-Michaél Hirsch.
Journal of Oral and Maxillofacial Surgery | 2009
Per Dérand; Jan-Michaél Hirsch
PURPOSE The purpose of this study was to investigate the possibility of virtually designing and manufacturing a template for reconstruction plate bending, to be used during treatment of congenital or acquired bony entities. The outcome was compared with plates bent by the freehand approach in a stereolithographic skull model. MATERIALS AND METHODS From a computed tomography examination, a polygon skull was created and the corresponding stereolithographic model retrieved. A polygon mesh of a Compact UniLock 2.4-mm plate was obtained from Synthes (Bettlach, Switzerland). The polygon plate was bent virtually around the mandible and rendered in all 3 dimensions, and a template was created. Five 10-hole plates were bent using this template, and five 10-hole plates were bent using a stereolithographic model as the template. The 2 groups were compared using the Wilcoxon signed rank test. P values less than .001 was considered to be statistically significant. RESULTS No statistical difference was seen between the 2 methods. The median discrepancy between the 2 groups was 0.1 mm. CONCLUSION Within the constraints of this investigation, by use of a virtually produced template based on a virtually planned reconstruction, it is possible to bend a reconstruction plate with the same degree of accuracy as that of the traditional freehand approach.
Qualitative Health Research | 2009
Marta Röing; Jan-Michaél Hirsch; Inger Holmström; Marja Schuster
When the mouth is affected by cancer, difficulties in satisfying basic human needs such as eating, tasting, swallowing, and speaking might arise, and the existential significance of the mouth might become obvious. How does it feel to live with these difficulties? What does it mean to be a human being living with the consequences of oral cancer? Five patients with oral cancer were interviewed a median time of 4 years after the beginning of treatment. A hermeneutic research approach was used to understand, explain, and interpret the transcribed interviews and showed how the consequences of oral cancer affected the being-in-the-world of the participants in three ways: existing as oneself, existing in the eyes of others, and existing with others. Against the background of the philosophy of Martin Heidegger, these findings illuminate how essential the mouth is to a human beings identity and existence.
Journal of Craniofacial Surgery | 2011
Daniel Nowinski; Elias Messo; Anders Hedlund; Jan-Michaél Hirsch
Virtual surgical planning and computer-aided surgery were used to treat a mono-ostotic fibrous dysplasia of the right zygoma. Mirroring of the contralateral zygoma sets the target for the contouring of the affected zygomatic bone. An optical system for computer-guided surgery was used. Instruments were calibrated and visualized in real time on screen. Achievement of the virtually set target for the orbitozygomatic anatomy was assessed during surgery. Postoperative computed tomography and clinical follow-up confirmed an excellent result with regard to facial symmetry and eye bulb position. The volume of the orbit was increased from 24.2 to 26.0 mL compared with a contralateral orbital volume of 25.7 mL. Computer-guided surgery may be a useful tool in the surgical reduction of craniofacial fibrous dysplasia.
Scandinavian Journal of Plastic and Reconstructive Surgery and Hand Surgery | 2008
Andreas Thor; Rafael Acosta Rojas; Jan-Michaél Hirsch
By preserving the temporomandibular joint (TMJ) disc in the glenoid fossa at the time of resection, correctly securing the vascularised fibular end in the fossa, and by reattaching the lateral pterygoid muscle, it is possible to maintain normal rotation, translatation, and protrusion in the TMJ and the function of the jaw can be totally restored. We describe four patients in whom good function was achieved in three; this is underlined by extensive remodelling of the condylar head seen at radiological follow-up up to 36 months.
Acta Oto-laryngologica | 2000
Lars Sand; Mats Wallström; Jamshid Jalouli; P-A Larsson; Jan-Michaél Hirsch
Epstein-Barr virus (EBV) and human papillomavirus (HPV) have been associated with benign as well as malignant oral lesions. We examined 43 patients with snuff-induced lesions and 22 control patients with clinically healthy oral mucosa for the presence of HPV and EBV. Polymerase chain reaction was performed on fresh frozen oral biopsies with degenerate consensus primers for HPV and nested primers for EBV. None of the 43 snuff-induced lesions or the 22 control biopsies were HPV-positive. Seven of the 43 (16.3%) snuff-induced lesions and one of the 22 (4.5%) controls were positive for EBV. The snuff-induced lesions were classified according to clinical severity, grade 1 lesions being the least severe and grade 4 the most severe. Eleven percent of grade 2 lesions, 15.8% of grade 3 lesions and 20% of grade 4 lesions were EBV-positive. Neither EBV nor HPV seem to be associated with snuff-induced lesions.Epstein-Barr virus (EBV) and human papillomavirus (HPV) have been associated with benign as well as malignant oral lesions. We examined 43 patients with snuff-induced lesions and 22 control patients with clinically healthy oral mucosa for the presence of HPV and EBV. Polymerase chain reaction was performed on fresh frozen oral biopsies with degenerate consensus primers for HPV and nested primers for EBV. None of the 43 snuff-induced lesions or the 22 control biopsies were HPV-positive. Seven of the 43 (16.3%) snuff-induced lesions and one of the 22 (4.5%) controls were positive for EBV. The snuff-induced lesions were classified according to clinical severity, grade 1 lesions being the least severe and grade 4 the most severe. Eleven percent of grade 2 lesions, 15.8% of grade 3 lesions and 20% of grade 4 lesions were EBV-positive. Neither EBV nor HPV seem to be associated with snuff-induced lesions.
Plastic and reconstructive surgery. Global open | 2015
Pontus Olsson; Fredrik Nysjö; Andres Rodriguez-Lorenzo; Andreas Thor; Jan-Michaél Hirsch; Ingrid B. Carlbom
Background: Virtual surgery planning has proven useful for reconstructing head and neck defects by fibula osteocutaneous free flaps (FOFF). Benefits include improved healing, function, and aesthetics, as well as cost savings. But available virtual surgery planning systems incorporating fibula in craniomaxillofacial reconstruction simulate only bone reconstruction without considering vessels and soft tissue. Methods: The Haptics-Assisted Surgery Planning (HASP) system incorporates bone, vessels, and soft tissue of the FOFF in craniomaxillofacial defect reconstruction. Two surgeons tested HASP on 4 cases they had previously operated on: 3 with composite mandibular defects and 1 with a composite cervical spine defect. With the HASP stereographics and haptic feedback, using patient-specific computed tomography angiogram data, the surgeons planned the 4 cases, including bone resection, fibula design, recipient vessels selection, pedicle and perforator location selection, and skin paddle configuration. Results: Some problems encountered during the actual surgery could have been avoided as they became evident with HASP. In one case, the fibula reconstruction was incomplete because the fibula had to be reversed and thus did not reach the temporal fossa. In another case, the fibula had to be rotated 180 degrees to correct the plate and screw placement in relation to the perforator. In the spinal case, difficulty in finding the optimal fibula shape and position required extra ischemia time. Conclusions: The surgeons found HASP to be an efficient planning tool for FOFF reconstructions. The testing of alternative reconstructions to arrive at an optimal FOFF solution preoperatively potentially improves patient function and aesthetics and reduces operating room time.
Journal of Materials Science: Materials in Medicine | 1998
Elisabeth Liljensten; Cecilia Larsson; Peter Thomsen; G. Blomqvist; Jan-Michaél Hirsch; C. Wedenberg
An insufficient quality and amount of bone often necessitate the clinical use of implants together with bone transplants. The present study describes an experimental animal model for the study of implants in bone grafts. Circular defects were made bilaterally in the tibia of 36 rabbits. The defects received either autologous cortical bone (control), demineralized bone matrix (DBM), plasma-augmented DBM or were left empty (without bone graft). In all defects a titanium implant was centrally placed and anchored in the opposite cortex. Evaluation with light microscopic morphometry showed that the insertion of a threaded titanium implant centrally in a cortical defect was followed by a spontaneous healing of the defect after 6 mon. After 6 wk, all implants in cortical grafts were well integrated with a significantly higher bone-to-implant contact than in the DBM and plasma-augmented groups. After 6 mon, all experimental groups had a mean bone area within the threads ranging between 69% and 80% and a mean bone-to-implant contact between 31% and 42%. The results from the present study indicate that the model allows comparative studies on the early formation, resorption and remodelling of bone around implants after modification of implant, graft and host properties.
world haptics conference | 2013
Pontus Olsson; Fredrik Nysjö; Jan-Michaél Hirsch; Ingrid B. Carlbom
Virtual assembly of complex objects has application in domains ranging from surgery planning to archaeology. In these domains the objective is to plan the restoration of skeletal anatomy or archaeological artifacts to achieve an optimal reconstruction without causing further damage. While graphical modeling plays a central role in virtual assembly, visual feedback alone is often insufficient since object contact and penetration is difficult to discern due to occlusion. Haptics can improve an assembly task by giving feedback when objects collide, but precise fitting of fractured objects guided by delicate haptic cues similar to those present in the physical world requires haptic display transparency beyond the performance of todays systems. We propose a haptic alignment tool that combines a 6 Degrees of Freedom (DOF) attraction force with traditional 6 DOF contact forces to pull a virtual object towards a local stable fit with a fixed object. The object forces are integrated into a virtual coupling framework yielding a stable haptic tool. We demonstrate the use of our system on applications from both cranio-maxillofacial surgery and archaeology, and show that we can achieve haptic rates for fractured surfaces with over 5000 points.
Journal of Craniofacial Surgery | 2016
Andreas Thor; Anders Palmquist; Jan-Michaél Hirsch; Lars-Erik Rännar; Per Dérand; Omar Omar
AbstractThere is limited information on the biological status of bone regenerated with microvascular fibula flap combined with biomaterials. This paper describes the clinical, histological, ultrastructural, and molecular picture of bone regenerated with patient-customized plate, used for mandibular reconstruction in combination with microvascular osteomyocutaneous fibula flap. The plate was virtually planned and additively manufactured using electron beam melting. This plate was retrieved from the patient after 33 months. Microcomputed tomography, backscattered-scanning electron microscopy, histology, and quantitative-polymerase chain reaction were employed to evaluate the regenerated bone and the flap bone associated with the retrieved plate. At retrieval, the posterior two-thirds of the plate were in close adaptation with the underlying flap, whereas soft tissue was observed between the native mandible and the anterior one-third. The histological and structural analyses showed new bone regeneration, ingrowth, and osseointegration of the posterior two-thirds. The histological observations were supported by the gene expression analysis showing higher expression of bone formation and remodeling genes under the posterior two-thirds compared with the anterior one-third of the plate. The observation of osteocytes in the flap indicated its viability. The present data endorse the suitability of the customized, additively manufactured plate for the vascularized fibula mandibular reconstruction. Furthermore, the combination of the analytical techniques provides possibilities to deduce the structural and molecular characteristics of bone regenerated using this procedure.
Medicina Oral Patologia Oral Y Cirugia Bucal | 2015
Miranda-Masoumeh Jalouli; Jamshid Jalouli; Bengt Hasséus; Jenny Öhman; Jan-Michaél Hirsch; Lars Sand
Background It has been estimated that 15%-20% of human tumours are driven by infection and inflammation, and viral infections play an important role in malignant transformation. The evidence that herpes simplex virus type 1 (HSV-1) could be involved in the aetiology of oral cancer varies from weak to persuasive. This study aimed to investigate by nested PCR (NPCR) the prevalence of HSV-1 in samples from normal oral mucosa, oral leukoplakia, and oral squamous cell carcinoma (OSCC). Material and Methods We investigated the prevalence of HSV-1 in biopsies obtained from 26 fresh, normal oral mucosa from healthy volunteers as well as 53 oral leukoplakia and 27 OSCC paraffin-embedded samples. DNA was extracted from the specimens and investigated for the presence of HSV-1 by nested polymerase chain reaction (NPCR) and DNA sequencing. Results HSV-1 was detected in 14 (54%) of the healthy samples, in 19 (36%) of the oral leukoplakia samples, and in 14 (52%) of the OSCC samples. The differences were not statistically significant. Conclusions We observed a high incidence of HSV-1 in healthy oral mucosa, oral leukoplakia, and OSCC tissues. Thus, no connection between OSCC development and presence of HSV-1 was detected. Key words:HSV-1, nested PCR, PCR.