Search PubMed⌕ Search

Biomedical subjects

C Gerber

Publications and source records attributed to C Gerber.

At least 19 recordsLinked to original sources
PubMed2000

Translating biomolecular recognition into nanomechanics.

We report the specific transduction, via surface stress changes, of DNA hybridization and receptor-ligand binding into a direct nanomechanical response of microfabricated cantilevers. Cantilevers in an array were functionalized with a selection of biomolecules. The differential deflection of the cantilevers was found to provide a true molecular recognition signal despite large nonspecific responses of individual cantilevers. Hybridization of complementary oligonucleotides shows that a single base mismatch between two 12-mer oligonucleotides is clearly detectable. Similar experiments on protein A-immunoglobulin interactions demonstrate the wide-ranging applicability of nanomechanical transduction to detect biomolecular recognition.

Animals↗
PubMed2000

Low temperature scanning force microscopy of the Si(111)-(7x7) surface

A low temperature scanning force microscope (SFM) operating in a dynamic mode in ultrahigh vacuum was used to study the Si(111)- (7x7) surface at 7.2 K. Not only the twelve adatoms but also the six rest atoms of the unit cell are clearly resolved for the first time with SFM. In addition, the first measurements of the short range chemical bonding forces above specific atomic sites are presented. The data are in good agreement with first principles computations and indicate that the nearest atoms in the tip and sample relax significantly when the tip is within a few A of the surface.

Journal Article↗
PubMed2000

MR imaging after rotator cuff repair: full-thickness defects and bursitis-like subacromial abnormalities in asymptomatic subjects.

OBJECTIVE: To determine the prevalence and extent of residual defects or retears and bursitis-like subacromial abnormalities on MR images after rotator cuff repair in asymptomatic subjects, and to define the clinical relevance of these findings. DESIGN AND PATIENTS: Fourteen completely asymptomatic patients and 32 patients with residual symptoms were investigated 27-53 months (mean 39 months) after open transosseous reinsertion of the rotator cuff. Coronal T2-weighted turbo spin-echo and turbo STIR or T2-weighted fat-suppressed MR images were obtained. The prevalence and extent of residual defects or retears of the rotator cuff and bursitis-like subacromial abnormalities were determined. RESULTS: Residual defects or retears were detected in three (21%) and bursitis-like abnormalities in 14 (100%) of the 14 asymptomatic patients. Fifteen (47%) residual defects or retears and 31 (97%) bursitis-like abnormalities were diagnosed in the 32 patients with residual symptoms. The size of the residual defects/retears was significantly smaller in the asymptomatic group (mean 8 mm, range 6-11 mm) than in the symptomatic group (mean 32 mm, range 7-50 mm) (t-test, P = 0.001). The extent of the bursitis-like subacromial abnormalities did not significantly differ (t-test, P > 0.05) between asymptomatic (mean 28 x 3 mm) and symptomatic patients (mean 32 x 3 mm). CONCLUSION: Small residual defects or retears (< 1 cm) of the rotator cuff are not necessarily associated with clinical symptoms. Subacromial bursitis-like MR abnormalities are almost always seen after rotator cuff repair even in patients without residual complaints. They may persist for several years after rotator cuff repair and appear to be clinically irrelevant.

Adult↗
PubMed2000

Posterior glenoid rim deficiency in recurrent (atraumatic) posterior shoulder instability.

OBJECTIVE: To assess the shape of the posterior glenoid rim in patients with recurrent (atraumatic) posterior instability. DESIGN AND PATIENTS: CT examinations of 15 shoulders with recurrent (atraumatic) posterior instability were reviewed in masked fashion with regard to abnormalities of the glenoid shape, specifically of its posterior rim. The glenoid version was also assessed. The findings were compared with the findings in 15 shoulders with recurrent anterior shoulder instability and 15 shoulders without instability. For all patients, surgical correlation was available. RESULTS: Fourteen of the 15 (93%) shoulders with recurrent (atraumatic) posterior shoulder instability had a deficiency of the posteroinferior glenoid rim. In patients with recurrent anterior instability or stable shoulders such deficiencies were less common (60% and 73%, respectively). The craniocaudal length of the deficiencies was largest in patients with posterior instability. When a posteroinferior deficiency with a craniocaudal length of 12 mm or more was defined as abnormal, sensitivity and specificity for diagnosing recurrent (atraumatic) posterior instability were 86.7% and 83.3%, respectively. There was a statistically significant difference in glenoid version between shoulders with posterior instability and stable shoulders (P=0.01). CONCLUSION: Recurrent (atraumatic) posterior shoulder instability should be considered in patients with a bony deficiency of the posteroinferior glenoid rim with a craniocaudal length of more than 12 mm.

Adolescent↗
PubMed2000

A cantilever array-based artificial nose

We present quantitative and qualitative detection of analyte vapors using a microfabricated silicon cantilever array. To observe transduction of physical and chemical processes into nanomechanical motion of the cantilever, swelling of a polymer layer on the cantilever is monitored during exposure to the analyte. This motion is tracked by a beam-deflection technique using a time multiplexing scheme. The response pattern of eight cantilevers is analyzed via principal component analysis (PCA) and artificial neural network (ANN) techniques, which facilitates the application of the device as an artificial chemical nose. Analytes tested comprise chemical solvents, a homologous series of primary alcohols, and natural flavors. First differential measurements of surface stress change due to protein adsorption on a cantilever array are shown using a liquid cell.

Journal Article↗
PubMed2000

Patient-controlled interscalene analgesia with ropivacaine 0.2% versus patient-controlled intravenous analgesia after major shoulder surgery: effects on diaphragmatic and respiratory function.

BACKGROUND: The authors compared the effects of patient-controlled interscalene analgesia (PCIA) with ropivacaine 0.2% and patient-controlled intravenous analgesia (PCIVA) with opioids on hemidiaphragmatic excursion and respiratory function after major shoulder surgery. METHODS: Thirty-five patients scheduled for elective major shoulder surgery were prospectively randomized to receive either PCIA or PCIVA. All patients received an interscalene block before surgery. In the PCIA group, a catheter was introduced between the anterior and middle scalene muscles. Six hours after the initial block, patients received for 48 h either a continuous infusion of 0.2% ropivacaine through the interscalene catheter at a rate of 5 ml/h plus a bolus dose of 3 or 4 ml with a lockout time of 20 min (PCIA group) or a continuous intravenous infusion of nicomorphine at a rate or 0.5 mg/h plus a bolus dose of 2 or 3 mg with a lockout time of 20 min (PCIVA group). Hemidiaphragmatic excursion and respiratory function were assessed with the patient in a 45 degrees semirecumbent position the day before the operation and 20 min (in the operating room), 24 h, and 48 h after the initial block by means of ultrasonography and spirometry, respectively. Pain relief was regularly assessed, side effects were noted, and patient satisfaction was rated 6 h after the end of the study. RESULTS: Hemidiaphragmatic excursion was similar in the two groups 20 min after interscalene block. Hemidiaphragmatic excursion was increased in the PCIA group on the nonoperated side 24 and 48 h after the interscalene block (P < 0.05). Pulmonary function was similar in the two groups at each time. Pain was better controlled in the PCIA group at 12 and 24 h (P < 0.05). The incidence of nausea and vomiting were 5.5% versus 60% for the PCIA and PCIVA groups, respectively (P < 0.05). Patient satisfaction was greater in the PCIA group (P < 0.05). CONCLUSIONS: The use of PCIA or PCIVA techniques to provide analgesia after major shoulder surgery is associated with similar effects on respiratory function. In the PCIA group, hemidiaphragmatic excursion showed a significantly greater amplitude 24 and 48 h after the initial block on the nonoperated side. The PCIA technique provided better pain control, a lower incidence of side effects, and a higher degree of patient satisfaction.

Adult↗
PubMed2000

Posterior-inferior capsular shift for the treatment of recurrent, voluntary posterior subluxation of the shoulder.

BACKGROUND: The treatment of recurrent posterior instability of the shoulder, especially when it is associated with voluntary subluxation, remains controversial, and operative correction generally is not advised. METHODS: The results of operative correction of recurrent posterior subluxation in a consecutive series of twenty-six shoulders in twenty-four patients were reviewed. Eighteen shoulders were on the dominant side. The average age of the patients was twenty-four years (range, fifteen to thirty-three years). All of the patients had involuntary as well as voluntary posterior instability, but none had a psychiatric disorder. Only five patients had sustained a definite injury that had initiated the instability. Seven shoulders had had previous operations. A program of nonoperative treatment for a duration of at least three months had failed to control the symptoms in all patients. The twenty-six shoulders were treated with a posterior-inferior capsular shift procedure, which included repair of a so-called posterior Bankart lesion in seven shoulders. In addition, one of the shoulders had a posterior bone block and three shoulders (in two patients) had an osteotomy of the posterior part of the glenoid because of excessive glenoid retroversion. The outcome was assessed by means of a personal interview and a clinical examination, which included calculations of a score according to the system of Constant and Murley and the performance of the Simple Shoulder Test, and by means of a radiographic examination, with standardized radiographs and computerized tomography scanning. RESULTS: At an average of 7.6 years (range, 1.8 to 14.6 years) after the operation, the patients estimated that the function of the shoulder was an average of 86 percent of that of a normal shoulder. The average relative score according to the system of Constant and Murley was 91 percent. The subjective result was excellent for sixteen shoulders, good for eight, and fair for two. More than half of all of the patients were able to perform all activities of the Simple Shoulder Test, but eight patients (eight shoulders; 31 percent) still had discomfort at night. Five patients (21 percent) changed their profession because of the shoulder. All but one shoulder had a nearly normal active range of motion. The instability recurred in six (23 percent) of the twenty-six shoulders; three recurrences were in shoulders that had had a primary operation, and three were in shoulders that had had an operation on the posterior aspect of the shoulder before the index procedure. The instability did not recur in four shoulders that had had previous operations on the anterior aspect of the shoulder. The subjective shoulder value, which was the patient's estimation of the value of the affected shoulder as a percentage of that of an entirely normal shoulder, was significantly higher for the stable shoulders (91 percent) than for the unstable shoulders (72 percent) (p<0.05). The relative score according to the system of Constant and Murley was also higher for the stable shoulders (93 percent) than for the unstable shoulders (87 percent), but the difference was not found to be significant, with the numbers available. The joints were found to be well centered radiographically, and only six shoulders showed minimum signs of osteoarthritis. Computerized tomography scanning revealed an average glenoid retroversion of 3.2 degrees (range, 17 degrees of retroversion to 22 degrees of anteversion). When only the shoulders that had not had a posterior bone block or an osteotomy of the posterior aspect of the glenoid were considered, the average glenoid retroversion of those that had recurrent instability was 12.5 degrees, whereas it was only 6.2 degrees for those that remained stable (p<0.05). CONCLUSIONS: Overall, operative correction of voluntary posterior instability of the shoulder yielded very satisfactory intermediate-term clinical results. (ABSTRACT TRUNCATED)

Adolescent↗
PubMed2000

Clinical outcome after structural failure of rotator cuff repairs.

BACKGROUND: The clinical outcome for patients with documented rerupture after open repair of one or more rotator cuff tendons is not well known. The purpose of this study was to evaluate the clinical outcomes of a consecutive series of rotator cuff reruptures after repair and to provide information concerning the advisability of rotator cuff repair in situations in which there may be a high probability of rerupture. METHODS: During prospective follow-up after rotator cuff repairs, we detected, with magnetic resonance imaging, structural failure of the repair in twenty patients, who had a mean age of fifty-nine years at the time of the rotator cuff repair. All patients were clinically examined for the purpose of this report at a mean of thirty-eight months. RESULTS: The reruptures invariably involved the originally torn tendon but were smaller than the original tear in sixteen of the twenty patients. Fatty degeneration of the supraspinatus and infraspinatus muscles, atrophy of the supraspinatus muscle, and glenohumeral osteoarthritis progressed significantly from the preoperative state (p < 0.05). At the time of the most recent follow-up, the subjective shoulder value averaged 75 percent of the value for a normal shoulder. Eleven patients were very satisfied with the result, six were satisfied, two were disappointed, and one was dissatisfied. The mean relative score according to the system of Constant and Murley had increased from 49 percent of the score for a normal shoulder preoperatively to 83 percent postoperatively (p = 0.0001). Pain had decreased significantly, and the ranges of active, pain-free forward elevation and abduction as well as the abduction strength had improved significantly (p < 0.05). The clinical outcome was significantly correlated with the size of the postoperative tear, the stage of postoperative fatty muscle degeneration of the infraspinatus and subscapularis, the postoperative acromiohumeral distance, and the degree of postoperative glenohumeral osteoarthritis (p < 0.05). CONCLUSIONS: This study documents that an attempt at rotator cuff repair significantly decreases pain (p = 0.0026) and significantly improves function (p = 0.0005) and strength (p = 0.0137) even if magnetic resonance imaging documents that the repair has failed. This finding suggests that the potential for rerupture should not be considered a formal contraindication to an attempt at repair if optimal functional recovery is the goal of treatment.

Aged↗
PubMed2000

The results of repair of massive tears of the rotator cuff.

BACKGROUND: Massive tears of the tendons of the rotator cuff cause atrophy and fatty degeneration of the rotator cuff muscles and painful loss of function of the shoulder. Repair of massive rotator cuff tears is often followed by retears of the tendons, additional muscular degeneration, and a poor clinical outcome. The purposes of this study were to determine whether a new method of repair of rotator cuff tendons can yield a lower retear rate and a better clinical outcome than previously reported methods, to assess the muscular changes following repair of massive tears of the musculotendinous units, and to correlate findings on magnetic resonance imaging with the clinical results. METHODS: Twenty-nine massive rotator cuff tears involving complete detachment of at least two tendons were repaired operatively with use of a new laboratory-tested technique in a prospective study. At least two years (average, thirty-seven months; range, twenty-four to sixty-one months) postoperatively, twenty-seven patients were evaluated clinically and with magnetic resonance imaging to determine the clinical outcome, the integrity of the repair, and the condition of the rotator cuff muscles. RESULTS: The age and gender-adjusted Constant score improved from an average of 49 percent preoperatively to an average of 85 percent postoperatively, corresponding to a subjective shoulder value of 78 percent of that of a normal shoulder. Pain-free flexion improved from an average of 92 degrees to an average of 142 degrees, and abduction improved from an average of 82 degrees to an average of 137 degrees. Pain decreased and performance of activities of daily living improved significantly (p < 0.05). The seventeen patients who had a structurally successful repair all had an excellent clinical outcome. Muscle atrophy could not be reversed except in successfully repaired supraspinatus musculotendinous units. Fatty degeneration increased in all muscles. CONCLUSIONS: The method of repair of massive rotator cuff tears that was used in this study yielded a comparatively low retear rate and good-to-excellent clinical results; however, the repair did not result in substantial reversal of muscular atrophy and fatty degeneration. Retears occurred more often in patients who had had a shorter interval between the onset of the symptoms and the operation (p < 0.05). Patients who had a retear had improvement of the shoulder compared with the preoperative state, but they had less improvement than did those who had a successful repair.

Activities of Daily Living↗
PubMed1999

Patient throughput times for orthopedic outpatients in a department of radiology: results of an interdisciplinary quality management program.

The purpose of this project was to employ quality management methods in order to decrease throughput times for orthopedic outpatients sent to the department of radiology. The following intervals were measured at the onset of the study and after 6 and 12 months: (a) between arrivals at outpatient clinic and radiology counter; (b) between arrival at radiology counter and time of last radiograph; and (c) between time of last radiograph and radiology report printing time. After the initial measurement, numerous changes were initiated both in radiology and in orthopedic surgery. The mean interval between arrival at the outpatient clinic and in radiology decreased by one third from 60 min during the first measurement to 40 (p < 0.001) and 41 min during the second and third measurement. The proportion of patients with total radiology times of more than 30 min decreased from 41 to 29 % between the first and third measurements (p < 0.001). The corresponding results for radiology times of more than 45 min were 17 and 11 % (p = 0.03). A standard type of quality management program can be employed successfully in order to reduce radiology throughput times for orthopedic outpatients.

Ambulatory Care↗
PubMed1999

Lesions of the reflection pulley of the long biceps tendon. MR arthrographic findings.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the diagnostic value of MR arthrography in detecting a lesion of the common insertion of the coracohumeral and the superior glenohumeral ligaments and the superior border of the subscapularis tendon (pulley lesion), which predisposes to biceps tendon subluxation and subsequent degeneration. METHODS: Parasagittal T1-weighted turbo spin-echo and axial gradient-echo (three-dimensional fast imaging with steady state-precession [FISP]) MR arthrographic images were obtained in 14 patients with surgically confirmed pulley lesions and in 10 patients with an intact pulley. Various MR arthrographic signs potentially associated with a pulley lesion were evaluated separately and independently in a blinded fashion by two radiologists. RESULTS: Abnormalities of the superior border of the subscapularis tendon on axial and parasagittal images, extra-articular contrast collection, and biceps tendon subluxation were the MR findings of a pulley lesion. The coracohumeral and superior glenohumeral ligaments were not readily visible in all patients and were not helpful in diagnosing pulley lesions in this study. The overall sensitivity for detecting a pulley lesion by MR arthrography was 86% and 93% for readers 1 and 2, with a specificity of 100% and 80% and an accuracy of 92% and 87% (kappa = 0.75). CONCLUSIONS: Based on the authors' experience, MR arthrography is valuable in detecting lesions of the reflection pulley of the long biceps tendon, although differentiation from an isolated lesion of the superior border of the subscapularis tendon may not be possible.

Adult↗
PubMed1999

Subscapularis tendon tears: detection and grading at MR arthrography.

PURPOSE: To assess diagnostic accuracy in the detection and grading of subscapularis tendon lesions at magnetic resonance (MR) arthrography. MATERIALS AND METHODS: MR arthrograms in 50 consecutive patients (29 with normal subscapularis tendons, 11 with a lesion in the cranial quarter, seven with a major tear but not complete detachment, three with complete detachment) with arthroscopic or surgical confirmation were evaluated independently by two radiologists. Diagnosis was established on findings from transverse and/or parasagittal images. RESULTS: With transverse images alone, sensitivity was 95%/100% (reader 1/reader 2); specificity was 55%/62%. With parasagittal images alone, sensitivity was 91%/91%; specificity was 76%/90%. With combined images, sensitivity was 91%/91%; specificity was 86%/79%. Interobserver agreement was substantial (kappa = 0.67). Forty-one of 50 (82%) grades for subscapularis abnormalities matched at MR imaging and surgery; nine mismatches differed by only one degree. Several signs were specific (90%-100%) but insensitive (29%-62%); these included leakage of contrast material onto the lesser tuberosity, fatty degeneration of the subscapularis muscle, and abnormality in the course of the long biceps tendon (luxation, subluxation). CONCLUSION: MR arthrography is accurate in the detection and grading of subscapularis tendon lesions. Specificity of findings on transverse images for this diagnosis can be improved by including indirect signs and findings on parasagittal images.

Adult↗
PubMed1999

Radiolucent lines and component stability in knee arthroplasty. Standard versus fluoroscopically-assisted radiographs.

The radiolucent lines and the stability of the components of 66 knee arthroplasties were assessed by six orthopaedic surgeons on conventional anteroposterior and lateral radiographs and on fluoroscopic views which had been taken on the same day. The examiners were blinded as to the patients and clinical results. The interpretation of the radiographs was repeated after five months. On fluoroscopically-assisted radiographs four of the six examiners identified significantly more radiolucent lines for the femoral component (p < 0.05) and one significantly more for the tibial implant. Five examiners rated more femoral components as radiologically loose on fluoroscopically-assisted radiographs (p = 0.0008 to 0.0154), but none did so for the tibial components. The mean intra- and interobserver kappa values were higher for fluoroscopically-assisted radiographs for both components. We have shown that fluoroscopically-assisted radiographs allow more reproducible, and therefore reliable, detection of radiolucent lines in total knee arthroplasty. Assessment of the stability of the components is significantly influenced by the radiological technique used. Conventional radiographs are not adequate for evaluation of the stability of total knee arthroplasty and should be replaced by fluoroscopically-assisted films.

Aged↗
PubMed1999

Experimental rotator cuff repair. A preliminary study.

BACKGROUND: The repair of chronic, massive rotator cuff tears is associated with a high rate of failure. Prospective studies comparing different repair techniques are difficult to design and carry out because of the many factors that influence structural and clinical outcomes. The objective of this study was to develop a suitable animal model for evaluation of the efficacy of different repair techniques for massive rotator cuff tears and to use this model to compare a new repair technique, tested in vitro, with the conventional technique. METHODS: We compared two techniques of rotator cuff repair in vivo using the left shoulders of forty-seven sheep. With the conventional technique, simple stitches were used and both suture ends were passed transosseously and tied over the greater tuberosity of the humerus. With the other technique, the modified Mason-Allen stitch was used and both suture ends were passed transosseously and tied over a cortical-bone-augmentation device. This device consisted of a poly(L/D-lactide) plate that was fifteen millimeters long, ten millimeters wide, and two millimeters thick. Number-3 braided polyester suture material was used in all of the experiments. RESULTS: In pilot studies (without prevention of full weight-bearing), most repairs failed regardless of the technique that was used. The simple stitch always failed by the suture pulling through the tendon or the bone; the suture material did not break or tear. The modified Mason-Allen stitch failed in only two of seventeen shoulders. In ten shoulders, the suture material failed even though the stitches were intact. Thus, we concluded that the modified Mason-Allen stitch is a more secure method of achieving suture purchase in the tendon. In eight of sixteen shoulders, the nonaugmented double transosseous bone-fixation technique failed by the suture pulling through the bone. The cortical-bone-augmentation technique never failed. In definite studies, prevention of full weight-bearing was achieved by fixation of a ten-centimeter-diameter ball under the hoof of the sheep. This led to healing in eight of ten shoulders repaired with the modified Mason-Allen stitch and cortical-bone augmentation. On histological analysis, both the simple-stitch and the modified Mason-Allen technique caused similar degrees of transient localized tissue damage. Mechanical pullout tests of repairs with the new technique showed a failure strength that was approximately 30 percent of that of an intact infraspinatus tendon at six weeks, 52 percent of that of an intact tendon at three months, and 81 percent of that of an intact tendon at six months. CONCLUSIONS: The repair technique with a modified Mason-Allen stitch with number-3 braided polyester suture material and cortical-bone augmentation was superior to the conventional repair technique. Use of the modified Mason-Allen stitch and the cortical-bone-augmentation device transferred the weakest point of the repair to the suture material rather than to the bone or the tendon. Failure to protect the rotator cuff post-operatively was associated with an exceedingly high rate of failure, even if optimum repair technique was used. CLINICAL RELEVANCE: Different techniques for rotator cuff repair substantially influence the rate of failure. A modified Mason-Allen stitch does not cause tendon necrosis, and use of this stitch with cortical-bone augmentation yields a repair that is biologically well tolerated and stronger in vivo than a repair with the conventional technique. Unprotected repairs, however, have an exceedingly high rate of failure even if optimum repair technique is used. Postoperative protection from tension overload, such as with an abduction splint, may be necessary for successful healing of massive rotator cuff tears.

Animals↗
PubMed1999

MR imaging for traumatic tears of the rotator cuff: high prevalence of greater tuberosity fractures and subscapularis tendon tears.

OBJECTIVE: The purpose of this study was to determine whether occult bony injuries or other characteristic MR abnormalities are frequent in patients suspected of having traumatic tears of the rotator cuff. SUBJECTS AND METHODS: MR arthrography of the shoulder was performed in 24 consecutive patients with suspected traumatic tears of the rotator cuff. MR findings were analyzed with regard to abnormalities of the supraspinatus, infraspinatus, and subscapularis tendons; and the humeral head. A comparison group of 24 consecutive patients with symptoms of nontraumatic tears of the rotator cuff was included in the investigation. RESULTS: Radiographically occult fractures of the greater tuberosity were found in nine (38%) of 24 patients with clinically suspected traumatic tears of the rotator cuff (seven of which occurred in patients <40 years old). Nine partial-thickness and five full-thickness supraspinatus tears were found in the trauma group. In the comparison group, the corresponding numbers were 13 and 10, respectively. Seven partial lesions of the cranial border of the subscapularis and six complete subscapularis tears (all six in patients >40 years old) were found in the trauma group (nine and one in the comparison group). CONCLUSION: Occult greater tuberosity fractures and complete subscapularis tears are commonly seen on MR images in patients suspected of having traumatic tears of the rotator cuff. Greater tuberosity fractures should be looked for specifically in patients younger than 40 years, and subscapularis tears should be looked for specifically in patients older than 40 years.

Adult↗
PubMed1998

Patient-controlled interscalene analgesia with ropivacaine after major shoulder surgery: PCIA vs PCA.

We have compared the efficacy of patient-controlled interscalene analgesia (PCIA) using ropivacaine with patient-controlled analgesia (PCA) using nicomorphine in 60 patients (n = 30 in each group), in a prospective, randomized study. In both groups, all patients received interscalene block with 0.75% ropivacaine before induction of anaesthesia. Six hours after interscalene block, patients in group PCIA received continuous infusion of 0.2% ropivacaine at a rate of 5 ml h-1 with a bolus dose of 3 or 4 ml and a lockout time of 20 min; patients in group PCA received continuous infusion of nicomorphine 0.5 mg h-1 and a bolus dose of 2 or 3 mg with a lockout time of 20 min. Control of pain was significantly better from 12 to 48 h after operation (except at 42 h) in group PCIA. Nausea and pruritus occurred significantly more frequently in group PCA. Patient satisfaction was greater in group PCIA. We conclude that the use of 0.2% ropivacaine using PCIA was an efficient way of managing pain after major shoulder surgery and compared favourably with PCA nicomorphine in terms of pain relief, side effects and patient satisfaction.

Adolescent↗