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Biomedical subjects

W N Dust

Publications and source records attributed to W N Dust.

7 recordsLinked to original sources
PubMed1998

Accuracy of intraoperative assessment of acetabular prosthesis placement.

Anteversion and vertical tilt of the acetabular prostheses in 50 consecutive total hip arthroplasties were prospectively evaluated during surgery (by the surgeon, using an alignment guide) and radiographically (calculated). From postoperative standardized radiographs vertical tilt was measured directly and anteversion was calculated. The mean error of vertical tilt was 5 degrees (range, 0 degrees - 20 degrees). The mean error of version was 9 degrees (range, 0 degrees - 24 degrees). The reliability of prosthesis placement in a predetermined zone was examined. Although the surgeons believed that all 50 cups were inside this zone, radiographic measurements revealed that 21 of the cups were actually outside. It is concluded that vertical tilt can be reasonably assessed during surgery. Anteversion, however, cannot be accurately assessed during surgery, despite use of the alignment guide.

Acetabulum↗
PubMed1997

A comparison of three regional anaesthesia techniques for outpatient knee arthroscopy.

PURPOSE: The purpose of this study was to compare intraoperative conditions and postoperative pain control of three peripheral regional anaesthesia techniques for outpatient knee arthroscopic procedures. METHODS: Sixty patients were randomized to one of three groups. Group 1A received portal injections (10 ml lidocaine 1%), intraarticular lidocaine (20 ml CO2 lidocaine 2% with 1/200,000 adrenaline) and a placebo femoral nerve block (20 ml saline). Group FNB received a femoral 3-in-1 nerve block (20 ml chloroprocaine 2% with 1/200,000 adrenaline), placebo portal injections (10 ml saline) and placebo intraarticular saline (20 ml saline with 1/200,000 adrenaline). Group FNB + IA received a femoral 3-in-1 nerve block, intraarticular lidocaine and placebo portal injections. The following were assessed: intraoperative pain (10 cm VAS: 0 = no pain, 10 = extreme pain), surgical operating conditions (1 = excellent, 4 = unacceptable), intraoperative use of sedation and analgesia, time to discharge, patient satisfaction score (1 = very satisfied, 5 very unsatisfied) and postoperative analgesia. Data were analyzed using ANOVA, Kruskal-Wallis, and Chi-square tests as appropriate, P < 0.05 was considered significant. RESULTS: There were no differences among the groups regarding any of the variables tested. Considerable post-operative pain (VAS > or = 5) was experienced by 20/54 (37%) patients. CONCLUSION: Any of the three anaesthetic techniques tested provide reliable intraoperative patient and surgical conditions for outpatient knee arthroscopy. Patient discomfort postoperatively was considerable in all groups and requires further investigation.

Adult↗
PubMed1997

Acute polyethylene fracture in an uncemented acetabular cup.

The smaller acetabular components used in total hip replacement may have a polyethylene liner that is too thin, resulting in higher polyethylene stress and an increased potential for wear. The authors present a case that highlights the problem of acute polyethylene fracture. To compensate for the thinness of the polyethylene, the authors recommend the use of a smaller head size to allow polyethylene thickness of at least 8 mm.

Acetabulum↗
PubMed1995

Radiographic calculation of anteversion in acetabular prostheses.

The position of the acetabular prosthesis is critical for preventing dislocation following total hip arthroplasty. The reliability of a mathematical model for radiographically calculated acetabular cup version was examined. A porous-coated anatomic acetabular prosthesis was mounted in a mold. Anteroposterior radiographs were taken with the cup in five different positions of anteversion. These were reviewed by five orthopaedic surgeons, and measurements were taken from each radiograph. From these measurements, the mathematically derived degree of version was calculated. The results were examined for accuracy and intraobserver reliability. It was concluded that intraobserver reliability was very good and that the accuracy was within a clinically acceptable range. This technique could be useful in studying the "safe zone" for acetabular prostheses.

Acetabulum↗
PubMedDate not supplied

The parasacral sciatic nerve block.

BACKGROUND AND OBJECTIVES: The clinical utility of a new parasacral approach for conduction block of the sciatic nerve was investigated, with critical examination of onset, extent, and success rates when this block was used for surgical procedures below the knee. METHODS: Thirty ASA I-III patients presenting for surgery on the lower limb were enrolled. All received 30 mL of 1.5% lidocaine with 1:200,000 epinephrine following nerve stimulator identification of the sciatic nerve at < or =0.2 mA or less. Trans-sartorial saphenous nerve blocks were performed to provide anesthesia to the medial leg. RESULTS: Overall success for surgical anesthesia with this block was 97%. All components of the sacral plexus could be blocked with this approach, and 93% of patients displayed evidence of obturator nerve motor block. However, no patient displayed evidence of obturator sensory anesthesia that could be mapped. Saphenous nerve blocks were 100% effective in providing surgical anesthesia for the procedures performed. CONCLUSIONS: The parasacral approach to the sciatic nerve exhibits a high success rate, resulting in anesthesia of the entire sacral plexus and generally in motor block of the obturator nerve was an interesting observation.

Adult↗
PubMedDate not supplied

Femoral nerve block. Single injection versus continuous infusion for total knee arthroplasty.

BACKGROUND AND OBJECTIVES: This study was conducted to ascertain whether there is any advantage to the continuous-infusion femoral 3-in-1 nerve block over the single-injection femoral nerve block for postoperative analgesia after total knee arthroplasty. METHODS: A double-blind, randomized, controlled study was made of 33 patients undergoing total knee arthroplasty, who were randomized into three groups. Group 1 received a single-injection femoral 3-in-1 nerve block with 20 mL 0.5% bupivacaine with 1:200,000 epinephrine. Group 2 had a catheter placed in the femoral nerve sheath, through which a continuous femoral 3-in-1 nerve block was established. Group 3 patients served as controls. All blocks were performed and assessed prior to induction of standardized general anesthesia. All patients received morphine via patient-controlled analgesia. Pain was recorded on a 100-mm visual analog scale at rest and with motion of the knee. Opioid consumption and side effects were recorded; P = .05 was considered statistically significant. RESULTS: In the recovery room, pain scores with motion were lower in the single-injection and continuous-infusion groups (P < .05). There were no significant differences between any of the groups regarding pain scores or morphine requirements beyond the recovery room. The incidence of nausea was higher in the control group. There were no differences between the groups with respect to overall patient satisfaction. CONCLUSIONS: We were unable to confirm improvements in analgesia provided by continuous-infusion femoral 3-in-1 nerve block for total knee arthroplasty except in the recovery room.

Aged↗