Objective: To compare the cup and stem position in matched pairs of cadaveric hips performing a m... more Objective: To compare the cup and stem position in matched pairs of cadaveric hips performing a minimally invaisve total hip arthroplasty (MIS-THA) either by using manual guidance tools or by the STRYKER Hip-track Navigation System. Background: Minimally invasive techniques are currently introduced to THA. Our workgroup has developed a direct anterior single incission approach. Special instruments have been designed for retraction and implantation. Instruments are navigable with the STRYKER hiptracksystem. Perfect positioning of the acetabular and femoral component are among the most important factors in THA. Malpositioning may result in significant clinical problems such as dislocation, impingement, limited range of motion or extensive wear. Design/Methods: In twelve fixated human cadavers hemispherical pressfit cups (TRIDENT, Stryker, Alledale, NJ) and straight femoral components (ACCOLADE, Stryker, Allendale, NJ) were implanted. All implantation were done throught the minimally invasive direct anterior approach. On one side the surgery was performed with spezial MIS instruments. On the oposite side the navigation system was used for placement of the implants. The aim was to achieve an alignment for the cups with 45° of inclination and 15° of anteversion in reference to the frontal pelvic plane. For the stem the goal was to position the stem in 0° of varus/valgus relative to the proximal shaft axes. This plane and the resulting cup positions were measured on CT-scans with a 3D imaging software (Stryker-Leibinger, Freiburg, Germany). Results: The Innsbruck MIS approach to the hip could be performed in all cases. For both groups cup and stem position where within the range of variation reported in the literature. Yet, variance of the deviation from the goal was higher in the conventional group for both inclination and anteversion with the medians for the navigated group for inclination, anteversion and stem position being closer to the goal then in the conventional group. Conclusion: The described minimally invasive approach to the hip is feasible and renders results compareable to those reported for conventionally operated THA. By the use of the navigation system tested it is possible to increase placement precission
Introduction: Minimally invasive total hip arthroplasty has evoked substantial controversy with r... more Introduction: Minimally invasive total hip arthroplasty has evoked substantial controversy with regard to whether it provides superior outcomes compared with conventional total hip arthroplasty. The objective of this study was to compare the results of a minimal invasive direct anterior approach (MIDA) with those of a conventional lateral transgluteal approach (CLT). Methods: 120 patients (120 hips) admitted for unilateral total hip arthroplasty were randomized to undergo surgery via minimal invasive direct anterior or conventional lateral transgluteal approach. Patients with a body mass index of more than 35, previous hip surgery, preoperative neurological deficits and with an age of more than 80 years were excluded. Two surgeons performed all procedures. To estimate muscle damage serum creatinkinase was assessed. Blood loss was calculated according to Rosencher by comparing preoperative to postoperative hematocrit. Postoperative pain and the ability to perform the activities of daily living were recorded in a dairy via modified WOMAC first on a daily basis, then on each second day and finally once a week for a total of 12 weeks. WOMAC questionnaire and SF-36 were administered at 6 weeks and 3 months follow-up. Results: The groups were similar demographically. Patients in MIDA group had significantly less total blood loss (p = 0.006), postoperative blood levels of creatinine kinase were significantly lower (p = 0.001). Operative time was similar in both groups, we found no difference in component placement. Physical component summary of SF-36 at 12 weeks follow-up showed a significant benefit for the MIDA group. Averaged modified WOMAC scores and their pain and function subscores demonstrated a clear advantage on every recorded day during the first 12 weeks for MIDA. Median WOMAC sum score and respective pain as well as function subscores were better in the MIDA group at 6 and 12 weeks follow up. Conclusions: A minimally invasive direct anterior approach is superior to a conventional lateral transgluteal approach with regard to blood loss and muscle trauma, resulting in better health related quality of life in the first three months after operation.
As described in an earlier chapter, the direct anterior approach is a single-incision approach. T... more As described in an earlier chapter, the direct anterior approach is a single-incision approach. The skin incision is made two fingerbreadths distal to the anterior superior iliac spine at the ventral border of the tensor fasciae latae muscle. The surgical portal lies between the lateral border comprised of the tensor muscle and the sartorius and rectus femoris muscle medially. The entire length of the incision will vary slightly depending on body habitus, but 8 cm is the typical incision length in our patient population. Special retractors developed for this procedure allow for excellent access to the acetabulum. With angulated reamer handles and cup introducers, acetabular preparation and cup implantation can be accomplished without the need for a larger incision. Femoral preparation and implantation are facilitated using special retractors that elevate the femur to a position that permits satisfactory access for stem preparation and using instruments with an anterior offset.
The approach is intended to allow for the implantation of a standard total hip prosthesis by the ... more The approach is intended to allow for the implantation of a standard total hip prosthesis by the use of standard instruments. Cemented as well as non-cemented implants can be used with this approach. However, the implantation process is facilitated with standard instruments that have undergone slight modification. In any minimally invasive approach the use of straight cup and stem inserters, straight cement-plug inserters and straight rigid reamers and broaches require more soft-tissue mobilization, which can cause excessive tension on these structures. Therefore, the use of instruments specifically developed for this approach is recommended.
A direct anterior approach is in use for minimally invasive total hip arthroplasty. This approach... more A direct anterior approach is in use for minimally invasive total hip arthroplasty. This approach uses an intermuscular and internerval plane between the sartorius, rectus femoris, and tensor fasciae latae. Although preparation of the acetabulum and implantation of the acetabular component is an easy task with the available instruments, preparation of the femoral canal through this single incision is more demanding. Instrumentation of the femur involves careful preparation of the dorsal capsule, positioning of the operated leg, and leverage of the femur. A broach handle with lateral and anterior offset for the direct anterior approach has been developed to reduce the need for leverage of the proximal femur for preparation of the cavity.
CARS 2002 Computer Assisted Radiology and Surgery, 2002
ABSTRACT Our purpose was the development and evaluation of a patient immobilization device and an... more ABSTRACT Our purpose was the development and evaluation of a patient immobilization device and an aiming device for frameless stereotactic interventional procedures in various body regions. For the CT scan the patient is placed upon a vacuum mattress, wrapped up with special cushions and covered with a plastic sheath. When the vacuum pump is turned on the cushions harden and the patient is sucked against the CT couch resulting in patient immobilization. After the scan the Vertek targeting device is adjusted using the StealthStation navigation system. The aiming device allows for precise alignment of the probe of the navigation system with the preplanned trajectory. The needle is advanced through the aiming device to the target. The novel technique was used for bone-tumor biopsies in 5 patients, vertebral-disc biopsy in two patients and –with a different immobilization technique-retrograde drilling of osteochondral lesions in the talus in 12 patients. Image-fusion revealed a needle displacement within 2-4 mms in all patients. The whole procedure including immobilization, general anaesthesia, adjustment of the targeting device and tissue sampling took about 1-2 hours per patient. Application of navigation systems in combination with the novel devices allows for precise puncturing of different targets in the body.
Navigation and Robotics in Total Joint and Spine Surgery, 2004
The concepts of minimally invasive surgery and computer-assisted surgery have recently come to th... more The concepts of minimally invasive surgery and computer-assisted surgery have recently come to the forefront of total hip arthroplasty (THA). These techniques have been borrowed from other surgical disciplines and have been introduced to Orthopedics independently. Minimally invasive techniques and surgical navigation have both been used, to some degree, in THA for several years, but only recently have the techniques been merged. With the introduction of specialty instruments and imageless navigation the combined technique has matured to a point were we can demonstrate a measurable early postoperative benefit and hopefully a long term benefit as measured by clinical outcome. Total hip arthroplasty is one of the most successful surgical procedures performed today. The history of THA is littered with attempts to improve outcome that have, with time, shown disappointing results. Few, however, would disagree with the goals of creating less soft tissue damage at the time of the procedure and being able to more accurately and reproducibly position the components; it being understood that long term hip function and implant survivorship are not decreased.
As described in an earlier chapter, the direct anterior approach is a single-incision approach. T... more As described in an earlier chapter, the direct anterior approach is a single-incision approach. The skin incision is made two fingerbreadths distal to the anterior superior iliac spine at the ventral border of the tensor fasciae latae muscle. The surgical portal lies between the lateral border comprised of the tensor muscle and the sartorius and rectus femoris muscle medially. The entire length of the incision will vary slightly depending on body habitus, but 8 cm is the typical incision length in our patient population. Special retractors developed for this procedure allow for excellent access to the acetabulum. With angulated reamer handles and cup introducers, acetabular preparation and cup implantation can be accomplished without the need for a larger incision. Femoral preparation and implantation are facilitated using special retractors that elevate the femur to a position that permits satisfactory access for stem preparation and using instruments with an anterior offset.
Objective: To compare the cup and stem position in matched pairs of cadaveric hips performing a m... more Objective: To compare the cup and stem position in matched pairs of cadaveric hips performing a minimally invaisve total hip arthroplasty (MIS-THA) either by using manual guidance tools or by the STRYKER Hip-track Navigation System. Background: Minimally invasive techniques are currently introduced to THA. Our workgroup has developed a direct anterior single incission approach. Special instruments have been designed for retraction and implantation. Instruments are navigable with the STRYKER hiptracksystem. Perfect positioning of the acetabular and femoral component are among the most important factors in THA. Malpositioning may result in significant clinical problems such as dislocation, impingement, limited range of motion or extensive wear. Design/Methods: In twelve fixated human cadavers hemispherical pressfit cups (TRIDENT, Stryker, Alledale, NJ) and straight femoral components (ACCOLADE, Stryker, Allendale, NJ) were implanted. All implantation were done throught the minimally invasive direct anterior approach. On one side the surgery was performed with spezial MIS instruments. On the oposite side the navigation system was used for placement of the implants. The aim was to achieve an alignment for the cups with 45° of inclination and 15° of anteversion in reference to the frontal pelvic plane. For the stem the goal was to position the stem in 0° of varus/valgus relative to the proximal shaft axes. This plane and the resulting cup positions were measured on CT-scans with a 3D imaging software (Stryker-Leibinger, Freiburg, Germany). Results: The Innsbruck MIS approach to the hip could be performed in all cases. For both groups cup and stem position where within the range of variation reported in the literature. Yet, variance of the deviation from the goal was higher in the conventional group for both inclination and anteversion with the medians for the navigated group for inclination, anteversion and stem position being closer to the goal then in the conventional group. Conclusion: The described minimally invasive approach to the hip is feasible and renders results compareable to those reported for conventionally operated THA. By the use of the navigation system tested it is possible to increase placement precission
Introduction: Minimally invasive total hip arthroplasty has evoked substantial controversy with r... more Introduction: Minimally invasive total hip arthroplasty has evoked substantial controversy with regard to whether it provides superior outcomes compared with conventional total hip arthroplasty. The objective of this study was to compare the results of a minimal invasive direct anterior approach (MIDA) with those of a conventional lateral transgluteal approach (CLT). Methods: 120 patients (120 hips) admitted for unilateral total hip arthroplasty were randomized to undergo surgery via minimal invasive direct anterior or conventional lateral transgluteal approach. Patients with a body mass index of more than 35, previous hip surgery, preoperative neurological deficits and with an age of more than 80 years were excluded. Two surgeons performed all procedures. To estimate muscle damage serum creatinkinase was assessed. Blood loss was calculated according to Rosencher by comparing preoperative to postoperative hematocrit. Postoperative pain and the ability to perform the activities of daily living were recorded in a dairy via modified WOMAC first on a daily basis, then on each second day and finally once a week for a total of 12 weeks. WOMAC questionnaire and SF-36 were administered at 6 weeks and 3 months follow-up. Results: The groups were similar demographically. Patients in MIDA group had significantly less total blood loss (p = 0.006), postoperative blood levels of creatinine kinase were significantly lower (p = 0.001). Operative time was similar in both groups, we found no difference in component placement. Physical component summary of SF-36 at 12 weeks follow-up showed a significant benefit for the MIDA group. Averaged modified WOMAC scores and their pain and function subscores demonstrated a clear advantage on every recorded day during the first 12 weeks for MIDA. Median WOMAC sum score and respective pain as well as function subscores were better in the MIDA group at 6 and 12 weeks follow up. Conclusions: A minimally invasive direct anterior approach is superior to a conventional lateral transgluteal approach with regard to blood loss and muscle trauma, resulting in better health related quality of life in the first three months after operation.
As described in an earlier chapter, the direct anterior approach is a single-incision approach. T... more As described in an earlier chapter, the direct anterior approach is a single-incision approach. The skin incision is made two fingerbreadths distal to the anterior superior iliac spine at the ventral border of the tensor fasciae latae muscle. The surgical portal lies between the lateral border comprised of the tensor muscle and the sartorius and rectus femoris muscle medially. The entire length of the incision will vary slightly depending on body habitus, but 8 cm is the typical incision length in our patient population. Special retractors developed for this procedure allow for excellent access to the acetabulum. With angulated reamer handles and cup introducers, acetabular preparation and cup implantation can be accomplished without the need for a larger incision. Femoral preparation and implantation are facilitated using special retractors that elevate the femur to a position that permits satisfactory access for stem preparation and using instruments with an anterior offset.
The approach is intended to allow for the implantation of a standard total hip prosthesis by the ... more The approach is intended to allow for the implantation of a standard total hip prosthesis by the use of standard instruments. Cemented as well as non-cemented implants can be used with this approach. However, the implantation process is facilitated with standard instruments that have undergone slight modification. In any minimally invasive approach the use of straight cup and stem inserters, straight cement-plug inserters and straight rigid reamers and broaches require more soft-tissue mobilization, which can cause excessive tension on these structures. Therefore, the use of instruments specifically developed for this approach is recommended.
A direct anterior approach is in use for minimally invasive total hip arthroplasty. This approach... more A direct anterior approach is in use for minimally invasive total hip arthroplasty. This approach uses an intermuscular and internerval plane between the sartorius, rectus femoris, and tensor fasciae latae. Although preparation of the acetabulum and implantation of the acetabular component is an easy task with the available instruments, preparation of the femoral canal through this single incision is more demanding. Instrumentation of the femur involves careful preparation of the dorsal capsule, positioning of the operated leg, and leverage of the femur. A broach handle with lateral and anterior offset for the direct anterior approach has been developed to reduce the need for leverage of the proximal femur for preparation of the cavity.
CARS 2002 Computer Assisted Radiology and Surgery, 2002
ABSTRACT Our purpose was the development and evaluation of a patient immobilization device and an... more ABSTRACT Our purpose was the development and evaluation of a patient immobilization device and an aiming device for frameless stereotactic interventional procedures in various body regions. For the CT scan the patient is placed upon a vacuum mattress, wrapped up with special cushions and covered with a plastic sheath. When the vacuum pump is turned on the cushions harden and the patient is sucked against the CT couch resulting in patient immobilization. After the scan the Vertek targeting device is adjusted using the StealthStation navigation system. The aiming device allows for precise alignment of the probe of the navigation system with the preplanned trajectory. The needle is advanced through the aiming device to the target. The novel technique was used for bone-tumor biopsies in 5 patients, vertebral-disc biopsy in two patients and –with a different immobilization technique-retrograde drilling of osteochondral lesions in the talus in 12 patients. Image-fusion revealed a needle displacement within 2-4 mms in all patients. The whole procedure including immobilization, general anaesthesia, adjustment of the targeting device and tissue sampling took about 1-2 hours per patient. Application of navigation systems in combination with the novel devices allows for precise puncturing of different targets in the body.
Navigation and Robotics in Total Joint and Spine Surgery, 2004
The concepts of minimally invasive surgery and computer-assisted surgery have recently come to th... more The concepts of minimally invasive surgery and computer-assisted surgery have recently come to the forefront of total hip arthroplasty (THA). These techniques have been borrowed from other surgical disciplines and have been introduced to Orthopedics independently. Minimally invasive techniques and surgical navigation have both been used, to some degree, in THA for several years, but only recently have the techniques been merged. With the introduction of specialty instruments and imageless navigation the combined technique has matured to a point were we can demonstrate a measurable early postoperative benefit and hopefully a long term benefit as measured by clinical outcome. Total hip arthroplasty is one of the most successful surgical procedures performed today. The history of THA is littered with attempts to improve outcome that have, with time, shown disappointing results. Few, however, would disagree with the goals of creating less soft tissue damage at the time of the procedure and being able to more accurately and reproducibly position the components; it being understood that long term hip function and implant survivorship are not decreased.
As described in an earlier chapter, the direct anterior approach is a single-incision approach. T... more As described in an earlier chapter, the direct anterior approach is a single-incision approach. The skin incision is made two fingerbreadths distal to the anterior superior iliac spine at the ventral border of the tensor fasciae latae muscle. The surgical portal lies between the lateral border comprised of the tensor muscle and the sartorius and rectus femoris muscle medially. The entire length of the incision will vary slightly depending on body habitus, but 8 cm is the typical incision length in our patient population. Special retractors developed for this procedure allow for excellent access to the acetabulum. With angulated reamer handles and cup introducers, acetabular preparation and cup implantation can be accomplished without the need for a larger incision. Femoral preparation and implantation are facilitated using special retractors that elevate the femur to a position that permits satisfactory access for stem preparation and using instruments with an anterior offset.
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