Sami Shimi - Academia.edu (original) (raw)
Papers by Sami Shimi
http://isrctn.org/>, 2000
http://isrctn.org/>, 2000
Endoscopic Surgery and Allied Technologies, Mar 1, 1995
Flexible access cannulae maintain a readily accessible tract for the efficient introduction and w... more Flexible access cannulae maintain a readily accessible tract for the efficient introduction and withdrawal of both straight and curved endoscopic instruments from skin to the parietes. Their main advantage is their capacity to deform, allowing the passage of curved instruments. Several designs of flexible access cannulae are currently available. The most practical design makes use of tightly coiled springs as tubes with or without silicone coating. A modification of this design uses wire woven into a tubular form and coated with silicone. Gas seal valves for these cannulae are currently primitive. The capacity of flexible access cannulae for deformation along the longitudinal and transverse axes could potentially be exploited for retrieval of small organs. Clinically, flexible cannulae have been used whenever curved instruments were needed. Coaxial curved and bayonet instruments have been used extensively in both thoracoscopic and laparoscopic operations. These instruments will allow an additional degree of freedom, that of the pre-formed curve of the instrument. In clinical terms this will facilitate the dissection, retraction and encirclement of tubular structures. In addition, the creation of intra-corporeal surgical knots is more efficient using curved needle holders.
Scottish medical journal, 1989
This is a case report of peptic ulcer perforation as a complication of double contrast Barium mea... more This is a case report of peptic ulcer perforation as a complication of double contrast Barium meal examination in the presence of gastric outlet obstruction.
Surgical Innovation, 1997
There has been increased recent interest in hepatic cryosurgery for primary and metastatic tumors... more There has been increased recent interest in hepatic cryosurgery for primary and metastatic tumors in the liver. This has been realized through technological advances in intraoperative ultrasound monitoring and cryoprobe technology. Purpose-designed needle implantable cryoprobes have been developed to freeze deep-seated tumors in the hepatic parenchyma. However, the biophysical and thermal characteristics of these implantable cryoprobes have not been studied. This article discusses the biophysical and thermal characteristics of recently developed high-efficiency, implantable needle cryoprobes that can be used laparoscopically. The cryolesion was formed along the whole length of the cryoprobe implanted into hepatic tissue. It was cylindrical in shape and extended 8 mm beyond the tip of the cryoprobe after 20 minutes of freezing. During this period of freezing, the volume of the cryolesion increased in a near constant manner, but the diameter increased in a logarithmic fashion. In addition, single-cycle freezing produced a larger cryolesion than a dual freeze cycle interrupted by a 5-minute thaw. Further, increasing the length of cryoprobe implantation increased the volume of the cryolesion, although the diameter was smaller. The rate of cooling at the tip of the cryoprobe was also faster with partial implantation of the cryoprobe than with complete implantation. The cooling rate varied vertically along the length of the cryoprobe, as well as horizontally from the cryoprobe.
Cryobiology, 1998
The objective of the investigation was to characterize the hepatic cryolesion formed with an impl... more The objective of the investigation was to characterize the hepatic cryolesion formed with an implantable needle (3 x 100 mm) cryoprobe. This was used to produce cryolesions in isolated porcine liver tissue equilibrated to 37 degrees C in a water bath. The shape, size, and temperature zones within the cryolesion and the effect of single versus repeated freeze-thaw cycles on cryolesion size were studied. The final shape of the cryolesion at 15-20 min freezing was cylindrical and its distal hemispherical end extended 8 mm beyond the tip of the cryoprobe. The rate of increase in maximum diameter was logarithmic and decreased from 4.7 mm/min during the first 5 min to 0.4 mm/min during the fourth 5-min period of freezing. By contrast, the rate of increase in volume was linear and ranged from 9.6 to 7.9 ml/min during the corresponding periods. The volume of the hepatic cryolesion after 20 min of continuous freezing was significantly greater than that of the cryolesion formed with 20 min of cumulative freezing interrupted by a 5-min spontaneous thaw. The ultimate temperatures reached and the cooling rates varied in different zones within the cryolesion depending on distances away from and alongside the cryoprobe. Diameter measurements taken in isolation do not reflect the actual growth rate of the cryolesion. Volume measurements define more accurately the amount of tissue frozen and left in situ. Prolonged freezing beyond 20 min did not increase the diameter of the cryolesion. A single continuous freeze produces a larger cryolesion than two freeze-thaw cycles of the same freezing duration.
Journal of the Royal College of Surgeons of Edinburgh, Sep 1, 1992
ABSTRACT
Journal of the Royal College of Surgeons of Edinburgh
ABSTRACT
Journal of the Royal College of Surgeons of Edinburgh
ABSTRACT
Journal of the Royal College of Surgeons of Edinburgh
ABSTRACT
Endoscopic surgery and allied technologies
New coaxial curved and bayonet instruments have been designed which permit controlled dissection ... more New coaxial curved and bayonet instruments have been designed which permit controlled dissection and directional change of the functional tip, blunt dissection and lift retraction. The instruments are introduced into the peritoneal and thoracic cavities through flexible re-usable metal cannulae. The excellent ergonomic properties of the new instruments have been confirmed by their use in major laparoscopic and thoracoscopic operations. Coaxial instruments enhance the scope of minimal access surgery and have distinct advantages over the traditional straight instruments.
Journal of the Royal College of Surgeons of Edinburgh, 1995
Efficient and safe dissection in laparoscopic surgery consists of the elements of exposure, tissu... more Efficient and safe dissection in laparoscopic surgery consists of the elements of exposure, tissue stabilization and tissue division. Exposure includes bulk exposure of organs and fine exposure of tissues during dissection. In endoscopic surgery this necessarily requires meticulous haemostasis. Tissue stabilization by atraumatic means displays the tissues with appropriate lines of tension to facilitate tissue division. This can be accomplished by a variety of energy types. Besides conventional dissection techniques, technologically advanced dissection systems employing different energy types have been incorporated in laparoscopic surgery. Mechanical energy sources such as ultrasound waves and the kinetic energy of a pressurized water-jet achieve precise dissection without haemostasis. However, thermal energy sources such as high-frequency electrosurgery and lasers achieve haemostatic dissection. Thermal methods generate destructive heat in the body which leads to coagulation or sepa...
Operative Manual of Endoscopic Surgery, 1992
Operationslehre der Endoskopischen Chirurgie 1, 1994
Operative Manual of Endoscopic Surgery, 1992
Operative Manual of Endoscopic Surgery, 1992
http://isrctn.org/>, 2000
http://isrctn.org/>, 2000
Endoscopic Surgery and Allied Technologies, Mar 1, 1995
Flexible access cannulae maintain a readily accessible tract for the efficient introduction and w... more Flexible access cannulae maintain a readily accessible tract for the efficient introduction and withdrawal of both straight and curved endoscopic instruments from skin to the parietes. Their main advantage is their capacity to deform, allowing the passage of curved instruments. Several designs of flexible access cannulae are currently available. The most practical design makes use of tightly coiled springs as tubes with or without silicone coating. A modification of this design uses wire woven into a tubular form and coated with silicone. Gas seal valves for these cannulae are currently primitive. The capacity of flexible access cannulae for deformation along the longitudinal and transverse axes could potentially be exploited for retrieval of small organs. Clinically, flexible cannulae have been used whenever curved instruments were needed. Coaxial curved and bayonet instruments have been used extensively in both thoracoscopic and laparoscopic operations. These instruments will allow an additional degree of freedom, that of the pre-formed curve of the instrument. In clinical terms this will facilitate the dissection, retraction and encirclement of tubular structures. In addition, the creation of intra-corporeal surgical knots is more efficient using curved needle holders.
Scottish medical journal, 1989
This is a case report of peptic ulcer perforation as a complication of double contrast Barium mea... more This is a case report of peptic ulcer perforation as a complication of double contrast Barium meal examination in the presence of gastric outlet obstruction.
Surgical Innovation, 1997
There has been increased recent interest in hepatic cryosurgery for primary and metastatic tumors... more There has been increased recent interest in hepatic cryosurgery for primary and metastatic tumors in the liver. This has been realized through technological advances in intraoperative ultrasound monitoring and cryoprobe technology. Purpose-designed needle implantable cryoprobes have been developed to freeze deep-seated tumors in the hepatic parenchyma. However, the biophysical and thermal characteristics of these implantable cryoprobes have not been studied. This article discusses the biophysical and thermal characteristics of recently developed high-efficiency, implantable needle cryoprobes that can be used laparoscopically. The cryolesion was formed along the whole length of the cryoprobe implanted into hepatic tissue. It was cylindrical in shape and extended 8 mm beyond the tip of the cryoprobe after 20 minutes of freezing. During this period of freezing, the volume of the cryolesion increased in a near constant manner, but the diameter increased in a logarithmic fashion. In addition, single-cycle freezing produced a larger cryolesion than a dual freeze cycle interrupted by a 5-minute thaw. Further, increasing the length of cryoprobe implantation increased the volume of the cryolesion, although the diameter was smaller. The rate of cooling at the tip of the cryoprobe was also faster with partial implantation of the cryoprobe than with complete implantation. The cooling rate varied vertically along the length of the cryoprobe, as well as horizontally from the cryoprobe.
Cryobiology, 1998
The objective of the investigation was to characterize the hepatic cryolesion formed with an impl... more The objective of the investigation was to characterize the hepatic cryolesion formed with an implantable needle (3 x 100 mm) cryoprobe. This was used to produce cryolesions in isolated porcine liver tissue equilibrated to 37 degrees C in a water bath. The shape, size, and temperature zones within the cryolesion and the effect of single versus repeated freeze-thaw cycles on cryolesion size were studied. The final shape of the cryolesion at 15-20 min freezing was cylindrical and its distal hemispherical end extended 8 mm beyond the tip of the cryoprobe. The rate of increase in maximum diameter was logarithmic and decreased from 4.7 mm/min during the first 5 min to 0.4 mm/min during the fourth 5-min period of freezing. By contrast, the rate of increase in volume was linear and ranged from 9.6 to 7.9 ml/min during the corresponding periods. The volume of the hepatic cryolesion after 20 min of continuous freezing was significantly greater than that of the cryolesion formed with 20 min of cumulative freezing interrupted by a 5-min spontaneous thaw. The ultimate temperatures reached and the cooling rates varied in different zones within the cryolesion depending on distances away from and alongside the cryoprobe. Diameter measurements taken in isolation do not reflect the actual growth rate of the cryolesion. Volume measurements define more accurately the amount of tissue frozen and left in situ. Prolonged freezing beyond 20 min did not increase the diameter of the cryolesion. A single continuous freeze produces a larger cryolesion than two freeze-thaw cycles of the same freezing duration.
Journal of the Royal College of Surgeons of Edinburgh, Sep 1, 1992
ABSTRACT
Journal of the Royal College of Surgeons of Edinburgh
ABSTRACT
Journal of the Royal College of Surgeons of Edinburgh
ABSTRACT
Journal of the Royal College of Surgeons of Edinburgh
ABSTRACT
Endoscopic surgery and allied technologies
New coaxial curved and bayonet instruments have been designed which permit controlled dissection ... more New coaxial curved and bayonet instruments have been designed which permit controlled dissection and directional change of the functional tip, blunt dissection and lift retraction. The instruments are introduced into the peritoneal and thoracic cavities through flexible re-usable metal cannulae. The excellent ergonomic properties of the new instruments have been confirmed by their use in major laparoscopic and thoracoscopic operations. Coaxial instruments enhance the scope of minimal access surgery and have distinct advantages over the traditional straight instruments.
Journal of the Royal College of Surgeons of Edinburgh, 1995
Efficient and safe dissection in laparoscopic surgery consists of the elements of exposure, tissu... more Efficient and safe dissection in laparoscopic surgery consists of the elements of exposure, tissue stabilization and tissue division. Exposure includes bulk exposure of organs and fine exposure of tissues during dissection. In endoscopic surgery this necessarily requires meticulous haemostasis. Tissue stabilization by atraumatic means displays the tissues with appropriate lines of tension to facilitate tissue division. This can be accomplished by a variety of energy types. Besides conventional dissection techniques, technologically advanced dissection systems employing different energy types have been incorporated in laparoscopic surgery. Mechanical energy sources such as ultrasound waves and the kinetic energy of a pressurized water-jet achieve precise dissection without haemostasis. However, thermal energy sources such as high-frequency electrosurgery and lasers achieve haemostatic dissection. Thermal methods generate destructive heat in the body which leads to coagulation or sepa...
Operative Manual of Endoscopic Surgery, 1992
Operationslehre der Endoskopischen Chirurgie 1, 1994
Operative Manual of Endoscopic Surgery, 1992
Operative Manual of Endoscopic Surgery, 1992