Purpose of this study is to create an experimental model of electrophysologic evaluation of the supraspinatus muscle on rats, after traumatic rupture of its tendon. The population of this study consisted of 10 male Sprague Dawley rats weighting 300–400g. Under general anaesthesia we proceeded with traumatic rupture of the supraspinatus tendon and exposure of the muscle. The scapula was immobilized, and the supraspinatus tendon was attached to a force transducer using a 3–0 silk thread. A dissection was performed in order to identify the suprascapular nerve, which was then stimulated with a silver electrode. Stimulations were produced by a stimulator (Digitimer Stimulator DS9A) and were controlled by a programmer (Digitimer D4030). Fiber length was adjusted until a single stimulus pulse elicited maximum force during a twitch under isometric conditions. Rectangular pulses of 0.5 ms duration were applied to elicit twitch contractions. During the recordings, muscles were rinsed with Krebs solution of approximately 37 8C (pH 7.2–7.4) and aerated with a mixture of 95% O2 and 5% CO2. The output from the transducer was amplified and recorded on a digital interface (CED). The following parameters were measured at room temperature (20–21 8C): single twitch tension; time to peak; half relaxation time; tetanic tensions at 10, 20, 40, 80 and 100 Hz; and fatigue index, which was evaluated using a protocol of low frequency (40 Hz) tetanic contraction, during 250 ms in a cycle of 1 s, for a total time of 180 s. The fatigue index value was then calculated by the formula [fatigue index=(initial tetanic tension − end tetanic tension) ∗ 100/(initial tetanic tension)]. In the end, the transducer was calibrated with standard weights and tensions were converted to grams. The mean single twitch was 8.2, the time to peak 0.034 msec and the half relaxation time 0.028 msec. The strength of titanic muscle contractures was 5.7 msec at 10Hz and 17.7 at 100Hz. Finally, the fatigue index was calculated at 48.4. We believe that electrophysiologic evaluation of the supraspinatus muscle in rats will help us understanding the pathology of muscle atrophy after rotator cuff tears and possibly the functional restoration after cuff repair
Retrospective study comparing the effectiveness of preoperative autologous blood donation versus intra-operative blood saver systems in minimizing the need for allogeneic blood transfusion in scoliosis surgery. Between 2003–2009, 37 of the patients (4–33, mean age 20y) who underwent scoliosis surgery, were divided in two groups. The first group (20 patients, mean age 18.7y) underwent autologous blood predonation, prerequisities were body weight over 50 kgr and Hgb above 11 mg/dl. The second group (17 patients, mean age 21.5y) consisted of patients who did not meet the above prerequisities and blood saver was used intra-operatively. Duration of surgery and perioperative Haemoglobulin (Hgb) levels were recorded in both groups.AIM
MATERIALS – METHODS
Intra-articular shoulder pathology has been recognised in more detail following widespread use of shoulder arthroscopy. The purpose of this epidemiological study is to present the incidence and exact type of SLAP lesions in our operated population and to correlate them with the presence of other shoulder lesions. Between 2004 and 2010 425 patients underwent shoulder arthroscopy in our department (311 for rotator cuff tears or subacromial impingement, 102 for shoulder instability, 12 for SLAP lesions). Eighty-two SLAP lesions (19.2% overall) were recognized during these procedures. In 44 cases the lesion was SLAP type I (53.6%), in 10 type II (12.2%), in 1 type III (1.2%), in 1 type IV (1.2%), in 24 type V (29.26%) and finally in 2 type VI (2.43%). In more detail SLAP I lesions were associated in 8 patients with subacromial impingement syndrome, in 33 with RC tear and in 3 patients with anterior instability. Type II, III and IV were preoperatively diagnosed, while type V and VI lesions were found in patients with chronic anterior shoulder instability. SLAP lesions are diagnosed more accurately during shoulder arthroscopy rather than with plain shoulder MRI scan. In our study population only 12 cases were accurately diagnosed with a pre-operative MRI scan, while the remaining 70 cases were missed. Additionally, there was significant correlation between rotator cuff problems and SLAP I lesions, while chronic shoulder instability was associated with SLAP V and VI (25.4% of patients with instability). Shoulder arthroscopy not only has changed SLAP lesion diagnosis and treatment but also reveals the correlation of various SLAP lesion types with specific shoulder pathologies.
