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At least 271 records · Page 15Linked to original sources

Practical biomechanical considerations for spine implant testing.

The author presents the basic biomechanical concepts linked with spine implant testing. The paper also contains the methodology of in vitro and in vivo spine implant testing. The physical and biological properties of various materials and devices commonly used in spine surgery are discussed in relation to their role in spine surgery. The paper clearly shows how all these parameters influence surgical strategy for the spine and more importantly how the choice of methods and devices influences the long term results of spinal surgery. The author also presents the biomechanical repercussions of a failed spine and his own concept of an "ideal" fusion.

Biomechanical Phenomena↗

[Benign tectal tumors: clinical and neuroradiological correlations].

Benign tectal tumours in children constitute a distinct group of brainstem gliomas, characterised by a usually benign clinical course. The aim of this paper was a retrospective analysis of 1) results of conservative treatment, 2) diagnostic value of CT and MRI and 3) correlation of the MR image with the clinical course of the disease. Our material includes 15 patients aged from 6 to 16. The treatment consisted in the implantation of a CSF-shunting device (6 children), endoscopic ventriculostomy (6 children) or ventriculostomy in a child with malfunction of a previously implanted shunt (3 cases). Follow-up periods range from 3 to 219 months (mean 46.8 mo.). A slight progression of tumour in imaging studies was noted in 3 cases, while in the remaining patients neither clinical nor radiologic progression of the disease was observed. There was no correlation between tumour size and focal contrast enhancement in MRI and the natural course of the disease. The method of choice in the diagnosis of benign tectal tumours is MRI and in the treatment of associated hydrocephalus-endoscopic third ventriculostomy. An in-depth diagnostic work-up and a more aggressive cause-oriented treatment is used only in cases of a documented clinical and radiological progression.

Adolescent↗

Cerebrospinal fluid seepage through polyglactin 910 dura substitute manifested as spinal extradural collection of fluid.

Following excision of pilocytic astrocytoma, a 12-year-old girl underwent posterior cranial fossa synthetic duraplasty with polyglactin 910 mesh. On the 8th postoperative day, unusual extradural collection was diagnosed by spinal magnetic resonance imaging. On the 14th postoperative day, cerebrospinal fluid leakage in the upper part of the postoperative wound was noticed. Unusual extradural collection detected by spinal magnetic resonance imaging was assumed to be the consequence of cerebrospinal fluid seepage and a warning sign of cerebrospinal fluid leakage following synthetic posterior fossa duraplasty. This case shows that polyglactin 910 mesh may be ineffective when used for posterior cranial fossa duraplasty in children, although it is considered as valuable as autologous tissue.

Astrocytoma↗

[Expandable stents and composite prosthesis].

Today, numerous expandable and mixed silicone metallic stents for trachea and bronchi are available. Among the many technical propositions, Nitinol is a new alloy with promising potential, offering the advantage of shape memory. The right stent is the one which best meets the needs of the individual stenotic situation as evaluated by endoscopy and CT. Sufficient experience has been acquired only with the Dumon stent, giving exact information about its qualities and possible complications. The new stents are thinner. Some can be inserted under fluoroscopic and fibroscopic control. They are presumed to produce fewer complications an provide answers to some still unresolved questions such as dyskinesia or stenosis on short bronchi. They appear to be more easily inserted on the tracheo-bronchial tree. More experience is needed to satisfactorily identify specific indications and contraindications. A prospective registry will be important to obtain comparative information more quickly.

Bronchi↗

[Revision surgery of otosclerosis: a review of 26 cases].

OBJECTIVES: The aim of this study was to identify causes of primary stapedectomy failures and to evaluate hearing results in revision stapes surgery. MATERIAL AND METHODS: We retrospectively reviewed a series of 26 revision stapedectomies. Patient characteristics, preoperative findings, causes of failure and complication of primary stapedectomy and postoperative hearing results were noted. RESULTS: Conductive hearing loss was the most common reason for revision surgery (77 %). Leading causes of stapedectomy failure included prosthesis malfunction (42 %), fibrous adhesions (37,5 %), incus erosion (12,5 %) and otosclerotic regrowth (12,5 %). When revision was indicated because of cochleo-vestibular complication, middle ear exploration revealed 3 problems: oval window granuloma or excessively long prosthesis or perilymphatic fistula. In this series, postoperative air-bone gap was closed to less than 10 dB in 57 % of cases, to less than 20 dB in 71 % of cases and we did not observed any sensorineural hearing loss. CONCLUSION: The results of this series are comparable with previously published studies. Revision stapes surgery is not as successful as primary stapedectomy, but the risk of sensorineural hearing loss does not appear to be higher than in primary surgery. Revision surgery is a challenging problem that must be performed by an experienced surgeon.

Adult↗

[Treatment of coxarthrosis with fitted total hip prostheses replacement].

The treatment of hip osteoarthritis with total hip arthroplasty has continuously evolved since it was first introduced in the sixties. The problem of aseptic loosening of the cemented prostheses, mainly in young active patients, has stimulated two different types of research: on one side the improvement of cementing techniques and on the other side the development of cementless osteoinegrable implants. We discuss the problems of these cementless hip prostheses. Recently published anatomic and biomechanic studies have led to the development of personalized custom femoral stems for each patient. The conception technique and first clinical results are described.

Adult↗

Acquired limb deficiencies. 4. Troubleshooting.

UNLABELLED: This self-directed learning module offers practical analyses of and solutions for common clinical problems of amputees. It is part of the chapter on acquired limb deficiencies in the Self-Directed Physiatric Education Program for practitioners and trainees in physical medicine and rehabilitation. The information presented here has been designed to be useful also to other interested professionals, including prosthetists, physical therapists, occupational therapists, and nurses. Topics covered include the management of typical obstacles encountered in upper limb amputees, and the diagnosis and treatment of phantom and residual limb pain. Diagnostic and treatment approaches to skin breakdown in the transtibial amputee and to knee instability in the transfemoral amputee are also presented. OVERALL ARTICLE OBJECTIVE: To analyze common clinical problems of amputees.

Amputation, Surgical↗

Local complications after limb-salvage surgery for pediatric bone tumours: a pictorial essay.

The prognosis for patients with bone sarcoma treated with LSS has improved considerably over the past 2 decades, but this has also lead to an increase in the number of complications requiring treatment. Imaging plays an important role, not only in assessing the primary tumour, but also in identifying postsurgical complications. Plain radiography demonstrates the majority of the complications associated with LSS and remains the mainstay of follow-up imaging. Complications such as fractures are common and warrant frequent plain film follow-up. Imaging with scintigraphy, MRI and CT should be tailored to the patient's clinical history, type of surgery and suspected complications. A baseline postoperative bone scan examination can be helpful for comparisons with subsequent scans for the detection of complications. Sonography should be considered if infection is suspected. Finally, tumour recurrence may be frequent enough to consider more extensive use of MRI.

Adolescent↗

Bone grafting from a restorative perspective--are we winning the space race?

The edentulous maxilla presents diverse and complex rehabilitation problems for the clinician that are often not addressed with a conventional removable appliance. Implant therapy, although revolutionizing the management of the edentulous mandible, has yielded less than favourable treatment outcomes in the maxilla. Poor bone quality and small bone volume in the maxilla, at the time of implant surgery has been associated with more implant and prosthesis failure. Bone grafting appears to improve the survival rate of implants in the atrophic maxilla and many studies have been published outlining techniques in which various types of implants have been used in conjunction with grafting materials. It is as yet not clear from the studies of maxillary grafting, whether various grafting materials are equally capable of supporting implants. The small number of patients and implants evaluated in many studies makes it difficult to predict specific outcomes for a single patient. The occurrence and frequency of complications with endosseous implant placement and with bone grafting is generally poorly defined. In the year 2000, our patients, third party insurers, the legal system and the scientific community are expecting more evidence to support the effectiveness of dental health care strategies. Evidence-based practice has become the catch cry for therapeutic intervention and yet the dental literature reveals a wide range of treatment modalities for which research can be at best considered weak. Studies to date into patient-based assessment of implant therapy provides little scientific evidence of substantially more benefit to edentulous patients with severe alveolar loss from implant therapy than was gained from alternative forms of treatment. Bone grafting and bone regenerative procedures do hold promise for the rehabilitation of the edentulous maxilla, however the Space Race is far from won.

Alveolar Ridge Augmentation↗

Artificial urinary sphincter implantation using a bulbous urethral cuff: perioperative care.

Urinary incontinence is a common problem encountered by clinicians and nursing staff. An artificial genitourinary sphincter (AGUS) placed around the bulbar urethra or bladder neck has become one of the gold standards for treating urinary incontinence due to sphincteric incompetence. It is imperative not only for physicians but also the nursing staff to have a working knowledge of the mechanics, risks, benefits, and durability of the AGUS to provide care for those patients encountered with an AGUS.

Humans↗

Dislocation following revision total hip arthroplasty.

Dislocation is a relatively common complication following revision total hip arthroplasty. Risk factors include surgical approach, gender, underlying diagnosis, comorbidities, surgical experience, and previous surgery; for later dislocations, risk factors include wear/deformation of polyethylene, trauma, and decreased muscle strength. Prevention and precaution are the watchwords for dislocations following revision total hip arthroplasty. For dislocations that do occur, treatment rests first on identifying the source of instability. Most dislocations can be managed by closed reduction. Constrained components may increase success rates, but only for appropriate indications. Prevention and treatment of dislocations following revision total hip arthroplasty are discussed in this article.

Casts, Surgical↗

Biliary stent causing colovaginal fistula: case report.

OBJECTIVES: Perforation of the bowel during placement of a biliary stent is a known complication of this procedure. We report the endoluminal loss of a biliary stent during routine stent extraction that ultimately led to a chronic colovaginal fistula. This case emphasizes the need for evaluation of fecal passage of stents in patients with a known dislodged prosthesis. CASE REPORT: A 65-year-old white female underwent biliary stent placement for an episode of choledocholithiasis. The stent was lost in the duodenum during routine extraction. The patient was managed expectantly. She denied ever passing this stent via the rectum and began to develop symptoms of colovaginal fistula. Evaluation found a retained biliary stent in the sigmoid colon and a fistula into the vagina. The patient underwent elective low anterior resection and colovaginal fistula repair. DISCUSSION: Reports exist of migration of stents that lead to acute colonic perforation and the need for emergent surgery. For this reason, it has been suggested that dropped or migrated stents be purposefully retrieved. However, if the option of expectant observation is used, it is important to clearly document the fecal passage of these stents and be prepared to retrieve these objects if they have a prolonged bowel transit time.

Aged↗

[Clinical investigation of extrusion of a new punctal plug(Flex Plug)].

PURPOSE: Punctal occlusion using punctal plugs is very effective for the treatment of tear-deficient dry eye. We compared the newly marketed Flex Plug (FP, Eagle Vision Co., Ltd.) and the Eagle Plug (EP, Eagle Vision Co., Ltd.). SUBJECTS AND METHODS: The subjects were patients with severe tear-deficient dry eye who were treated in our dry eye clinic. FP plugs in 8 patients (9 eyes) and EP plugs in 29 patients (35 eyes) were compared during over 4 months of observation with regard to the time until extrusion and the possibility for re-insertion of the plugs. RESULTS: During the 4 months after insertion of the plugs, the EP plugs were extruded from 35 of 51 puncta (68.6%) and the FP plugs were extruded from 4 of 13 puncta (30.8%). In the 35 EP extrusions and in the 4 FP extrusions, re-insertion was possible. The time period until extrusion was longer for FP than for EP. In all cases, for both EP and FP, pyogenic granuloma was not observed. DISCUSSION: The extrusion rate for EP plugs was much greater than for FP plugs (68.6% to 30.8%). Pyogenic granuloma was not observed in any instance for both types of punctal plugs.

Aged↗

How close does an uncemented hip stem match the final rasp position?

During total hip arthroplasty the final clinical position of the cementless CLS stem (Centerpulse) is not always identical to the position of the final rasp with which a successful trial reduction was performed. Therefore, the rasp-stem correspondence of CLS system (Centerpulse) was investigated in a laboratory study and compared to the CBC-T system (Mathys). Both systems showed an average rasp-stem mismatch below 2 mm in three orthogonal directions. It was found that this mismatch related to geometric differences at the corners between rasp and stem. The measured mismatch is not expected to have adverse clinical consequences.

Arthroplasty, Replacement, Hip↗

Surgical-handling properties of the titanium prosthesis in ossiculoplasty.

Despite the wide variety of ossiculoplasty techniques that are available, success rates are limited. Current use indicates that surgeons prefer ceramic, autograft bone, and plastic pore prostheses. During the past decade, titanium prostheses have been used with great promise. Although their use is not widespread, satisfaction rates are high. An earlier study of ossiculoplasty showed that titanium prostheses were effective in reducing conductive hearing loss. To date, the surgical-handling attributes of titanium middle ear prostheses have not been assessed. We report the results of our survey of 32 otologic surgeons who used the open Tübingen titanium prosthesis for primary and revision ossiculoplasty during tympanoplasty in 400 patients at 12 academic and nonacademic otolaryngology clinics, most of them in Germany. Because the audiometric efficacy of titanium prostheses has been previously reported, our primary outcomes measures included ease of use with respect to the amount of time required to prepare the implants for placement and the surgeons' overall impression of the intraoperative handling characteristics of the implants, taking into consideration factors such as positioning, length adjustment, visibility, and the stability of the coupling. Surgeons also compared the properties of the titanium implant with those of gold, ceramic, and autograft implants that they had used in the past. Based on the results of 383 of the 400 ossiculoplasties, our survey revealed that the titanium implant was significantly superior to the others in all measured respects.

Adult↗

Humeral component modularity may not be an important factor in the outcome of shoulder arthroplasty for glenohumeral osteoarthritis.

We examined the outcomes of using 3 types of humeral prostheses in total shoulder arthroplasty for osteoarthritis: a modular prosthesis with variable head diameters (MV), a nonmodular prosthesis with variable head diameters (NV), and a nonmodular prosthesis with a fixed head diameter (NF). Patients (N=101) completed self-assessments of shoulder function and health status before surgery and at follow-up between 30 and 60 months after surgery. Outcomes for the MV and NV prostheses did not differ statistically. The NF prosthesis trended toward poorer functional scores. Two Short Form-36 dimensions were statistically significantly lower (P<.05) in the NF group than in the MV and NV groups. These results fail to confirm that humeral component modularity is an important factor in the outcome of shoulder arthroplasty.

Aged↗