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Computer-aided reconstruction of large skull defects
524
Technology - Surgical Approaches and Endoscopy
rate was 61.5%. The methods of craniofacial reconstruction with use of rotated and especially vascularized tissue lIaps with costal fragments permit restoration of the lacial skeleton and provide good cosmetic results.
I0-7-1 01 I Computer-aided reconstruction of large skull defects M. Lorenz, G. Graubner, H. Schumann 1, U. Hustedt". M. Samii. Klinik, Zentrale Forschungswerkstatten, 2 AbteilungfUr Neuroradiologie, Medizinische HochschuleHannover, 0-30623 Hannover, Germany
1 Neurochirurgische
Introduction: Large bony skull defects usually occur after decompressive craniectomy. Typically, the shape contains different curvatures. The indication for a plastic reconstruction is to facilitate a normalization of the ICP-dynamtcs, and cosmetical reasons. A freehand reconstruction will fulfill the physical requirements but often misses a sufficient cosmetical result. Patients and Method: A new procedure of an anatomically exact reconstruction was developed and is under further improvement: 1. Skull-data were sampled by 3D-CT. 2. These data were converted into commands that control a milling machine to produce a laminar accumulated model. 3. Thereafter, a Palacosv-lrnplant was made. Initially, a positive form showing the defect was used. In the last time, the lacking surface could be calculated by mirroing the data of the other side. This is of valuable help in modelling the implant and opens the possibility for a direct manufacturing of the lIap. First resultsare very satisfying. However, the production has to be improved because it is still too time consuming to establish it as a routine-process. Results and Conclusion: In 19 patients a new designed way of an anatomically correct reconstruction of large skull delects was used and relined. This procedure was chosen especially in alert persons wrth the demand of an optimal result. The produced models matched the anatomical form very good and the patients were very satisfied with the cosmetical result. The effort and costs will be justified in those patients who will recover full social activities. A Palaces'[- implant will allow subsequent MR-imaging. The lurther development of a primary implant-production may lead to implants at other places, such as for the closure of basal defects after removal of huge tumors.
I0-7-102 1 Ventricular lavage system Newton Paes. Universidade de Santo Amaro, Sao Paulo, Brazil The management of patients at risk lor cranial hypertension continues to be a controversial subject. O'Sullivan, et at, have concluded that even severely head injured patients whose initial CT scan is normal or does not show a mass lesion, midline shift, or effaced cisterns nevertheless remain at risk lor developing significant secondary cerebral insults due to elevated ICP, reduced CPP, and hypotensiondespite aggressiveintensive care. Ischemiabeginswhen cerebral perfusion pressure lalls below 50 mmHg, and when CPP is below 30 mmHg severe, irreversible ischemia occurs. Since CPP is equal to mean arterial pressure minus ICP, the monitoring of ICP has proved to be a useful tool in the management 01 these patients. ICP can be lowered with diuretics, hyperventilation or barbiturate therapy. In addition, the drainage of CSF can be particularly useful in lowering IC? Currently ICP moniloring and drainage are independent 01 each other. The author presents the design theory and initial animal studies of a new microprocessor based device designed to both monitor and control ICP by automatic extraction of micro volumes 01 CSF. The system consists of a double lumen catheter connected to an extemal double pump system with pressure monitor and micro-processor based controller. ICP is monitored through the catheter and ICP is controlled by the extraction 01 small volumes of CSF.The software and microprocessor controller permit the control of ICP to avoid hypertension. In addition, software permits the determination of brain compliance to trend the progress of the patient. The system may also be used for infusion and extraction of physiologic solutions to aid in the eliminationof blood clots. It is anticipated that this device may proveto be uselul in preventing intracranial hypertension in cases of intraventricular hemorrhage, subarachnoid hemorrhage, post surgical tumor removal, hydrocephalUS and traumatic brain edema.
10 -7-103 1 EndC?scopy-assisted microsurgery of cramopharyngeomas Erik Van Lindert, Axel Pemeczky, Christoph Busert. Department of Neurosurgery, Universityof Mainz, Mainz, Germany Introduction: With the intention to reduce the surgical trauma in skull base surgery, we gradually reduced the size of our surgical approaches. This change has been made possible by individual approach planning and by intraoperative useof endoscopy.This study should evaluate the resultsof endoscopy-assisted keyhole approacheslor craniopharyngeomas.
Monda); 7 July 1997
Methods: We retrospectively studied the clinical files of 14 palients (M:F
=6:8) operated on between 1993 and 1996. Patient ages ranged from 14-63
yrs (average; 40 yrs). Seven patients presented with recurrent tumors, 5 of them operated on elsewhere. The approaches that were used were: supraorbital (8), transventricular/transforaminal (2), transcaliosaVtransventricular (2), presigmoidal (1), subtrontal interhemispheric (1). Results: In 5 cases tumor resectionwas performed truly endoscopy-assisted (so-called videosurgery). In 9 cases endoscopy was used for inspection after completed microsurgical tumor exstirpation. In three of these cases tumor remnants were lound endoscopically, which then could be removed under endoscopic control. In all 14 patients gross total removal could be achieved. Ten patients had a good result, however most 01 them with hormonal substitution. Two patients had a moderate outcome, one 01 them with amnestic syndrome, the other with a psychosyndrome and an oculomotor nerve palsy. Two patients died: one patient six weeks after surgery of pulmonary embolism and sepsis, the other 5 months after surgery due to electrolyte disturbances. There was no tumor recurrence after a mean follow-up of 28 months in the other 12 patients. Conclusion: We conclude that intraoperative endoscopy is an adequate tool that helps to achieve radical tumor removal in craniopharyngeoma surgery, even for recurrent tumors. The combination 01 individual approach planning by the keyhole conceptand intraoperative endoscopy is benelicial to a patient with a craniopharyngeoma by reducing surgical traumatization.
I0-7-1041 Image-directed neuroendoscopy N.L. Dorward" O. Alberti 1 , J. Zha0 2 , D. Hawkes 2 , J. Buurrnan-', A. Dijkstra, D.G.T. Thomas 1. ' Institute of Neurology. London, UK, 2 Radiological Sciences, Guy s Hospital, London, UK, 3 Philips Medical Systems, Best, Netherlands Introduction: Both minimallyinvasive surgery and image guidancecan improve outcome and reduce hospital stay. Until now they have largely been approached as altemative not complementary techniques. Our aimwas to combinethe power of navigation with the minimally invasive qualities of neuroendoscopy. Methods: We have Easy Guide Neuro (Philips Medical Systems) for navigation and a rigid 24 cm 4 channel neuroendoscope (Aesculap AG). An array of light emitting diodes was produced for attachment to the endoscope, enabling the guidance system to track the tip. Live orthogonal reformats of the pre-operative MRI showed the tip position. Such reformats were also produced at a known distance ahead 01 the endoscope tip through Virtual elongation of the endoscope, chosen to correspond with the field 01 view. Results: The ability 01 the system to accurately localise the endoscope tip and the accuracy 01 virtual tip elongation reformatting have been verified through phantom studies. These revealed a mean localisation error for the standardpointer of 0.63 mm with a standard deviation of 0.58 mm and with the endoscope of 0.67 and 0.53 mm respectively. The system has been tested in the clinical setting and proven to be 01considerable value. Discussion: This work has resulted not only in image-guidance of the endoscope but also in interactive endoscopy. The former enables the surgeon to preciselytailor the incision,burr hole(s) and approach to the individualpatient, to guide the normally blind insertion of the endoscope and provide orientation at all times. The latter is the novel ability to display the wider anatomy beyond the endoscope view and beyond the CSF spaces in an iterative manner. This is a powerful 1001with real clinical potential. Research funded by EEC Telematics in Surgery Project.
I0 -7-1051 Endoscopy-assisted skull base surgery Yong Ko, Kwang-Myung Kim, Suck-Jun Oh. Hanyang University Hospitsl, Seoul, Korea Wide skin and bony exposure including the lace is current policy in the management of skull base tumors. Even though this aggressive surgery saved many lives, it did not result in a better quality 01 lile. In the present series miniature craniotomy near the skull base and endoscopy were used to reduce morbidity. In a period of3 years 13 patients were operated with the diagnosis of skull base meningioma,chordoma, rhabdomyosarcoma, metastaticadenocarcinoma and neurilemmoma. Small superolateral orbital roof craniotomy was done to operate anterior and middle cranial base tumors. Retromastoid craniectomy with or without removal of C1 arch sufficed for posterior fossa tumors. Most of tumors could be removed through a mini-window. Remnant tumors behind the petrous bone and at the contralateral side were effectively removed under endoscopic visualization. Good anatomical relationship between tumor and brain could be observed with zero and thirty degree endoscopes. However, endoscopic surgery had limitations in the dissection 01 highly vascular tumors since it could not control massive bleeding. A rigid endoscope was usually used during surgery and a flexible endoscope was additionally used to see hidden areas. Our technique resulted in less scar, facial deformity and morbidity. Endoscopic surgery can satisfactorily help neurosurgeons to control skull base tumors with a small incision, and restricted craniotomy.
Technology - Surgical Approaches and Endoscopy
rate was 61.5%. The methods of craniofacial reconstruction with use of rotated and especially vascularized tissue lIaps with costal fragments permit restoration of the lacial skeleton and provide good cosmetic results.
I0-7-1 01 I Computer-aided reconstruction of large skull defects M. Lorenz, G. Graubner, H. Schumann 1, U. Hustedt". M. Samii. Klinik, Zentrale Forschungswerkstatten, 2 AbteilungfUr Neuroradiologie, Medizinische HochschuleHannover, 0-30623 Hannover, Germany
1 Neurochirurgische
Introduction: Large bony skull defects usually occur after decompressive craniectomy. Typically, the shape contains different curvatures. The indication for a plastic reconstruction is to facilitate a normalization of the ICP-dynamtcs, and cosmetical reasons. A freehand reconstruction will fulfill the physical requirements but often misses a sufficient cosmetical result. Patients and Method: A new procedure of an anatomically exact reconstruction was developed and is under further improvement: 1. Skull-data were sampled by 3D-CT. 2. These data were converted into commands that control a milling machine to produce a laminar accumulated model. 3. Thereafter, a Palacosv-lrnplant was made. Initially, a positive form showing the defect was used. In the last time, the lacking surface could be calculated by mirroing the data of the other side. This is of valuable help in modelling the implant and opens the possibility for a direct manufacturing of the lIap. First resultsare very satisfying. However, the production has to be improved because it is still too time consuming to establish it as a routine-process. Results and Conclusion: In 19 patients a new designed way of an anatomically correct reconstruction of large skull delects was used and relined. This procedure was chosen especially in alert persons wrth the demand of an optimal result. The produced models matched the anatomical form very good and the patients were very satisfied with the cosmetical result. The effort and costs will be justified in those patients who will recover full social activities. A Palaces'[- implant will allow subsequent MR-imaging. The lurther development of a primary implant-production may lead to implants at other places, such as for the closure of basal defects after removal of huge tumors.
I0-7-102 1 Ventricular lavage system Newton Paes. Universidade de Santo Amaro, Sao Paulo, Brazil The management of patients at risk lor cranial hypertension continues to be a controversial subject. O'Sullivan, et at, have concluded that even severely head injured patients whose initial CT scan is normal or does not show a mass lesion, midline shift, or effaced cisterns nevertheless remain at risk lor developing significant secondary cerebral insults due to elevated ICP, reduced CPP, and hypotensiondespite aggressiveintensive care. Ischemiabeginswhen cerebral perfusion pressure lalls below 50 mmHg, and when CPP is below 30 mmHg severe, irreversible ischemia occurs. Since CPP is equal to mean arterial pressure minus ICP, the monitoring of ICP has proved to be a useful tool in the management 01 these patients. ICP can be lowered with diuretics, hyperventilation or barbiturate therapy. In addition, the drainage of CSF can be particularly useful in lowering IC? Currently ICP moniloring and drainage are independent 01 each other. The author presents the design theory and initial animal studies of a new microprocessor based device designed to both monitor and control ICP by automatic extraction of micro volumes 01 CSF. The system consists of a double lumen catheter connected to an extemal double pump system with pressure monitor and micro-processor based controller. ICP is monitored through the catheter and ICP is controlled by the extraction 01 small volumes of CSF.The software and microprocessor controller permit the control of ICP to avoid hypertension. In addition, software permits the determination of brain compliance to trend the progress of the patient. The system may also be used for infusion and extraction of physiologic solutions to aid in the eliminationof blood clots. It is anticipated that this device may proveto be uselul in preventing intracranial hypertension in cases of intraventricular hemorrhage, subarachnoid hemorrhage, post surgical tumor removal, hydrocephalUS and traumatic brain edema.
10 -7-103 1 EndC?scopy-assisted microsurgery of cramopharyngeomas Erik Van Lindert, Axel Pemeczky, Christoph Busert. Department of Neurosurgery, Universityof Mainz, Mainz, Germany Introduction: With the intention to reduce the surgical trauma in skull base surgery, we gradually reduced the size of our surgical approaches. This change has been made possible by individual approach planning and by intraoperative useof endoscopy.This study should evaluate the resultsof endoscopy-assisted keyhole approacheslor craniopharyngeomas.
Monda); 7 July 1997
Methods: We retrospectively studied the clinical files of 14 palients (M:F
=6:8) operated on between 1993 and 1996. Patient ages ranged from 14-63
yrs (average; 40 yrs). Seven patients presented with recurrent tumors, 5 of them operated on elsewhere. The approaches that were used were: supraorbital (8), transventricular/transforaminal (2), transcaliosaVtransventricular (2), presigmoidal (1), subtrontal interhemispheric (1). Results: In 5 cases tumor resectionwas performed truly endoscopy-assisted (so-called videosurgery). In 9 cases endoscopy was used for inspection after completed microsurgical tumor exstirpation. In three of these cases tumor remnants were lound endoscopically, which then could be removed under endoscopic control. In all 14 patients gross total removal could be achieved. Ten patients had a good result, however most 01 them with hormonal substitution. Two patients had a moderate outcome, one 01 them with amnestic syndrome, the other with a psychosyndrome and an oculomotor nerve palsy. Two patients died: one patient six weeks after surgery of pulmonary embolism and sepsis, the other 5 months after surgery due to electrolyte disturbances. There was no tumor recurrence after a mean follow-up of 28 months in the other 12 patients. Conclusion: We conclude that intraoperative endoscopy is an adequate tool that helps to achieve radical tumor removal in craniopharyngeoma surgery, even for recurrent tumors. The combination 01 individual approach planning by the keyhole conceptand intraoperative endoscopy is benelicial to a patient with a craniopharyngeoma by reducing surgical traumatization.
I0-7-1041 Image-directed neuroendoscopy N.L. Dorward" O. Alberti 1 , J. Zha0 2 , D. Hawkes 2 , J. Buurrnan-', A. Dijkstra, D.G.T. Thomas 1. ' Institute of Neurology. London, UK, 2 Radiological Sciences, Guy s Hospital, London, UK, 3 Philips Medical Systems, Best, Netherlands Introduction: Both minimallyinvasive surgery and image guidancecan improve outcome and reduce hospital stay. Until now they have largely been approached as altemative not complementary techniques. Our aimwas to combinethe power of navigation with the minimally invasive qualities of neuroendoscopy. Methods: We have Easy Guide Neuro (Philips Medical Systems) for navigation and a rigid 24 cm 4 channel neuroendoscope (Aesculap AG). An array of light emitting diodes was produced for attachment to the endoscope, enabling the guidance system to track the tip. Live orthogonal reformats of the pre-operative MRI showed the tip position. Such reformats were also produced at a known distance ahead 01 the endoscope tip through Virtual elongation of the endoscope, chosen to correspond with the field 01 view. Results: The ability 01 the system to accurately localise the endoscope tip and the accuracy 01 virtual tip elongation reformatting have been verified through phantom studies. These revealed a mean localisation error for the standardpointer of 0.63 mm with a standard deviation of 0.58 mm and with the endoscope of 0.67 and 0.53 mm respectively. The system has been tested in the clinical setting and proven to be 01considerable value. Discussion: This work has resulted not only in image-guidance of the endoscope but also in interactive endoscopy. The former enables the surgeon to preciselytailor the incision,burr hole(s) and approach to the individualpatient, to guide the normally blind insertion of the endoscope and provide orientation at all times. The latter is the novel ability to display the wider anatomy beyond the endoscope view and beyond the CSF spaces in an iterative manner. This is a powerful 1001with real clinical potential. Research funded by EEC Telematics in Surgery Project.
I0 -7-1051 Endoscopy-assisted skull base surgery Yong Ko, Kwang-Myung Kim, Suck-Jun Oh. Hanyang University Hospitsl, Seoul, Korea Wide skin and bony exposure including the lace is current policy in the management of skull base tumors. Even though this aggressive surgery saved many lives, it did not result in a better quality 01 lile. In the present series miniature craniotomy near the skull base and endoscopy were used to reduce morbidity. In a period of3 years 13 patients were operated with the diagnosis of skull base meningioma,chordoma, rhabdomyosarcoma, metastaticadenocarcinoma and neurilemmoma. Small superolateral orbital roof craniotomy was done to operate anterior and middle cranial base tumors. Retromastoid craniectomy with or without removal of C1 arch sufficed for posterior fossa tumors. Most of tumors could be removed through a mini-window. Remnant tumors behind the petrous bone and at the contralateral side were effectively removed under endoscopic visualization. Good anatomical relationship between tumor and brain could be observed with zero and thirty degree endoscopes. However, endoscopic surgery had limitations in the dissection 01 highly vascular tumors since it could not control massive bleeding. A rigid endoscope was usually used during surgery and a flexible endoscope was additionally used to see hidden areas. Our technique resulted in less scar, facial deformity and morbidity. Endoscopic surgery can satisfactorily help neurosurgeons to control skull base tumors with a small incision, and restricted craniotomy.