Articles: surgery.
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Comparative Study
[Placement of pedicle screws using different navigation systems. A laboratory trial with 12 spinal preparations].
A well-known problem occurring with thoracolumbar spondylodesis is the perforation of pedicle screws through the pedicle wall. It occurs in up to 40% of the implanted screws. To reduce this problem, computed tomography (CT)-based navigation systems have been introduced, which allow the surgeon multidimensional control of the screw position in virtual reality and real time during insertion. ⋯ We inserted 77 pedicle screws in human lumbar cadaveric spine specimens either without navigation, with CT-based navigation, or with fluoroscopy-based navigation. In the critical sizes of pedicles between 6.5 and 9 mm, we found the best results with CT-based navigation, but there was no significant difference between the three methods. The minimal pedicle and the screw diameters should be reported in every study on pedicle screw misplacement and spine navigation since they represent the most important factor in pedicle wall perforations.
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Computer assisted navigation-based surgery is a novel and interesting challenge for todays surgeons. One must however keep in mind, that the indications for these techniques (a) should be carefully considered, (b) used only if morbidity is not increased and (c) when previously problematic or inacurate surgical methods can be improved upon. ⋯ Percutaneous retrograde drilling (cf. [6, 7, 9, 15, 20, 21]) spared the joint's cartilage in all cases. At the level of the knee joint we see the usefulness of this method for complex situations (cf. [12, 13]) requiring precise drilling.
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There is a rapid increase of computer-assisted surgery (CAS) in the spine for insertion of pedicle screws. In contrast to the traditional technique using fluoroscopy, CT is the primary source for surgical navigation systems. ⋯ In experienced hands open pedicle screw insertion in the thoracic and lumbar spine using fluoroscopy-control requires a fifteen times lower radiation dose than do CT scans necessary for computer-assisted surgery. Regarding the published small percentage of neurological complications in traditional screw insertion technique the use of computer-assisted surgery in pedicle screw insertion using CT scan should be limited to carefully chosen indications. The development of navigation systems based on other data sources than CT should be encouraged.
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Patients who do not improve after lumbar surgery may be given the nonspecific label of "failed back surgery syndrome (FBSS)." Since 1981, there has not been a quantitative assessment of the etiologies of FBSS despite major improvements in surgical techniques and diagnostic testing. ⋯ We were able to establish a predominant diagnosis in 94% of our patients. Foraminal stenosis remains the leading cause of FBSS, but painful discs are also common. Recurrent disc herniation is seen less often than in the past, and there is increased recognition of neuropathic pain. Knowledge of the potential causes of FBSS leads to a more efficient and cost-effective evaluation of these patients.
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Plast. Reconstr. Surg. · Mar 2002
Clinical TrialCranial reconstruction with computer-generated hard-tissue replacement patient-matched implants: indications, surgical technique, and long-term follow-up.
The aim of this clinical study was to evaluate the effectiveness and safety of using computer-generated alloplastic (hard-tissue replacement) implants for the reconstruction of large defects of the upper craniofacial region. Fourteen patients who had large (> 150 cm2) preexisting defects of the cranium or cranio-orbital region underwent surgical reconstruction. Preoperatively, a three-dimensional computed tomographic scan was obtained from which an anatomic model was fabricated. ⋯ In large cranial defects, custom implants fabricated from porous, hydrophilic hard-tissue replacement polymer provide an exacting anatomic fit and a solid stable reconstruction. This method of reconstruction in these defects is rapid and exact, and significantly reduces operative time. Critical attention must be paid, however, to management of the frontal sinus and preexisting bone infection and the quality of the overlying soft-tissue cover.