Letter.

There are many implications for patient dignity and confidentiality if staff wear body cams, but if interactions are recorded it could help prevent difficult situations from escalating.

Ultrasound reduces the minimum effective local anaesthetic volume compared with peripheral nerve stimulation for interscalene block.

BACKGROUND: Previous studies have demonstrated that lower local anaesthetic (LA) volumes can be used for ultrasound (US)-guided interscalene brachial plexus block (ISB). However, no study has examined whether US can reduce the volume required when compared with nerve stimulation (NS) for ISB. Our aim was to do this by comparing the minimum effective analgesic volumes (MEAVs). METHODS: After ethics approval and informed consent, patients undergoing shoulder surgery were recruited to this randomized, double-blind, up-down sequential allocation study. The volume used for both US and NS was dependent upon the success or failure of the previous block. Success was defined as a verbal rating score of 0/10, 30 min after surgery. Ten needle passes were allowed before defaulting to the opposite group. Patients received general anaesthesia. Pain scores and analgesic consumption were assessed by a blinded observer. Statistical comparisons of continuous variables were performed using Student's t-test and Mann-Whitney U-test as appropriate. Categorical variables were analysed using χ² test. MEAV values were estimated using log-transformed up-down independent pairs analysis and probit regression. Significance was assumed at P<0.05 (two-sided). RESULTS: The MEAV required to provide effective analgesia was significantly (P=0.034) reduced to 0.9 ml [95% confidence interval (CI) 0.3-2.8] in the US group from 5.4 ml (95% CI 3.4-8.6) in the NS group. Fewer needle passes were needed to identify the brachial plexus with US (1 vs 3; P<0.0001) and patients had less pain at 30 min after surgery (P=0.03). CONCLUSIONS: US reduces the number of attempts, LA volume, and postoperative pain when compared with NS for ISB.

Effect of local anaesthetic volume (20 vs 5 ml) on the efficacy and respiratory consequences of ultrasound-guided interscalene brachial plexus block.

BACKGROUND: Interscalene brachial plexus block (ISBPB) is an effective nerve block for shoulder surgery. However, a 100% incidence of phrenic nerve palsy limits the application of ISBPB for patients with limited pulmonary reserve. We examined the incidence of phrenic nerve palsy with a low-volume ISBPB compared with a standard-volume technique both guided by ultrasound. METHODS: Forty patients undergoing shoulder surgery were randomized to receive an ultrasound-guided ISBPB of either 5 or 20 ml ropivacaine 0.5%. General anaesthesia was standardized. Both groups were assessed for respiratory function by sonographic diaphragmatic assessment and spirometry before and after receiving ISBPB, and after surgery. Motor and sensory block, pain, sleep quality, and analgesic consumption were additional outcomes. Statistical comparison of continuous variables was analysed using one-way analysis of variance and Student's t-test. Non-continuous variables were analysed using chi(2) tests. Statistical significance was assumed at P<0.05. RESULTS: The incidence of diaphragmatic paralysis was significantly lower in the low-volume group compared with the standard-volume group (45% vs 100%). Reduction in forced expiratory volume in 1 s, forced vital capacity, and peak expiratory flow at 30 min after the block was also significantly less in the low-volume group. In addition, there was a significantly greater decrease in postoperative oxygen saturation in the standard-volume group (-5.85 vs -1.50, P=0.004) after surgery. There were no significant differences in pain scores, sleep quality, and total morphine consumption up to 24 h after surgery. CONCLUSIONS: The use of low-volume ultrasound-guided ISBPB is associated with fewer respiratory and other complications with no change in postoperative analgesia compared with the standard-volume technique.

Chondromyxoid fibroma of the acromium with soft tissue extension.

Chondromyxoid fibroma is an unusual, benign tumor of cartilaginous origin and represents less than 1% of all primary bone tumors. It usually involves the long bones around the knee joint or the flat bones of the pelvis or ribs. Soft tissue extension is also thought to be rare in these lesions. They are usually eccentrically located in the metaphyses of the long bones and centrally in the flat bones. The radiographic appearances are characteristically those of a single, lytic lesion with lobulated margins, septations, cortical expansion and a sclerotic rim. Histologically, they display a lobulated pattern with spindle-shaped cells lying within a myxoid matrix with areas of hyaline cartilage. The differential diagnosis includes giant cell tumor, chondroblastoma or enchondroma as well as chondrosarcoma. The rarity of these lesions may render the diagnosis difficult to make, especially when the lesion involves an unusual site such as the acromium.

Effect of nabumetone on hemostasis during arthroscopic knee surgery.

The known effects of commonly used nonsteroidal anti-inflammatory drugs (NSAIDs) on hemostatic parameters have led to concern over their use in the perioperative period. Nabumetone, unlike other NSAIDs, has little effect on collagen-induced platelet aggregation. To evaluate the effect of nabumetone 2000 mg daily on other hemostatic parameters (e.g., bleeding time, prothrombin time, and partial thromboplastin time) in the clinical setting, this double-masked study was conducted in patients with osteoarthritis undergoing arthroscopic knee surgery. After a 1-week placebo washout period, 58 patients were randomized to receive nabumetone and 53 were randomized to receive placebo. They were assessed before surgery (after 1 to 2 weeks of treatment) and again after surgery (after an additional 3 weeks of treatment). The study was designed to have 90% power to show equivalence in bleeding time to within 1.5 minutes, a difference assumed to be of no clinical importance. No meaningful differences were observed between the groups in any of the measured hemostatic parameters. Before surgery, the bleeding time increased by only 0.3 minutes with nabumetone and decreased by 0.2 minutes with placebo. The mean (+/- SD) difference between the groups in change from baseline was 0.5 +/- 0.3 minutes. After surgery, the changes were 0.1 minutes and 0.0 minutes, respectively, and the difference between groups was 0.2 +/- 0.3 minutes. These differences were neither statistically nor clinically significant, and maximum individual increases were similar in each group. Furthermore, there were no reports of abnormal bleeding in the operative knees. The results of this study show that nabumetone had little or no effect on hemostasis and suggest that this drug can be used safely in the perioperative period.

Osteonecrosis and resorption of the patella after total knee replacement: a case report.

A 54-year-old woman with a history of right total knee replacement had right knee pain and swelling for 6 months. Radiographs of the knee showed significant fragmentation and resorption of the patella consistent with osteonecrosis. Evidence of increased anteroposterior laxity was noted on physical examination. Revision surgery to a posterior stabilized prosthesis with excision of the patellar fragments resulted in a marked improvement in her symptoms and functional capabilities 2 years after surgery. The authors review the blood supply to the patella and how it may be disturbed by knee surgery and speculate that this patient's symptoms may have been worsened by the anteroposterior instability of her prosthesis.

Centrode characteristics of the lumbar spine as a function of segmental instability.

A cadaveric study provides a quantitative measurement of early degenerative disc disease before significant radiographic changes are present. Accurate assessment of spinal motion is hampered by the inaccessibility of the lumbar joints and because of the small range of motion at each motion segment. Using Moiré fringes and, more recently, computerized digitization of spinal motion, the authors have developed a technique of measuring centers of rotation for small ranges of motion. The centers of rotation when joined form a locus that has characteristics that allow one to identify spines with degenerative disc disease. These loci, or centrodes, are longest in the earliest stages of degeneration, but maintain their length through moderate degenerative disc disease. Furthermore, radiographic changes consistent with moderate disc disease are associated with inferior migration of the centrode.

Centrode patterns and segmental instability in degenerative disc disease.

Moiré fringes were used to determine centrode patterns in cadaveric spines with degenerative disc disease. The normal centrodes were compared with those with minor, mild, moderate, and severe degenerative disc disease. The most complex loci noted were those discs that showed minimal radiographic evidence of degeneration, that is, the minor and mild groups. The loci lengthened significantly (P less than 0.001) when compared with normal controls. The position of the centrode shifted downward into the body of L5 in the moderate group.

Determination of a locus of instantaneous centers of rotation of the lumbar disc by moiré fringes. A new technique.

The aim of this study was to define the motion of the L4-5 spinal segment moving from full extension to full flexion. A new technique using moiré fringes was applied to measure angles of 3-degree change, a technique proven to be highly accurate for small angular changes. This investigation has identified a locus of centers of rotation (centrode) that is located in the posterior half of the intervertebral disc. The direction of the locus passes from posterior to anterior and back to posterior. The technique can be adapted for evaluation of in vivo radiographs. This technique may prove useful in identifying aberrations in movement associated with spinal segment instability in its earliest stages.