Learning curve in relation to radiation exposure, procedure duration and complications rate for Minimally Invasive Chevron Akin (MICA) osteotomy.

BACKGROUND: Minimally invasive chevron Akin osteotomy (MICA) has become increasingly common and is compatible with the traditional open approaches for hallux valgus correction. However, it is impeded by concerns regarding the steep learning curve, increased radiation exposure and some specific complications. No standardized method for identifying a learning curve exists. We used a reproducible mathematical model to accurately define the learning curve of MICA with a focus on fluoroscopy time, procedure duration and complications rate. METHODS: We conducted a retrospective study of MICA procedure performed by a single surgeon during his initial experience with this procedure. The chronologic case number was plotted against variables of interest and learning was identified as the point at which instantaneous rate of change of a curve fit to the data set equalled the average rate of change of the data set. RESULTS: One hundred cases have been analysed. Learning plateau in operation time was achieved after 29 cases, with the first 29 cases requiring a median of 60 min compared to 40 min for the latter 71 cases. Proficiency in fluoroscopy application occurred in case 30. The median fluoroscopy time for the first 30 cases was 86 seconds compared to 70 seconds in another 70 cases. The complication rate plateau was reached after 42 cases, with 15 of 22 complications occurring in the group operated first. CONCLUSION: Results demonstrate surgeon's comfort with MICA to minimize operative time and radiation exposure after 30 cases. The plateau is achieved later for complications. Findings impose lag between surgeon feeling comfortable with procedure and a decrease in complications. Further research is reasonable to analyse several surgeons learning curve and to generate a potential reference learning curve that could serve as a normative. TRIAL REGISTRATION: UKC-MB-KME-33/19, retrospectively registered.

Early neonatal universal ultrasound screening for developmental dysplasia of the hip: a single institution observational study.

OBJECTIVE: We evaluated the effect of early universal ultrasound (US) screening program for developmental dysplasia of the hip (DDH). METHODS: A total of 21,676 newborns between 2006 and 2015 were included in the study. All hips were examined by US within the first week of life. The incidence of sonographic hip-types according to the Graf method was analyzed, and then followed prospectively. Risk factors for DDH and treatment measures were also recorded, together with the number of first surgical procedures before the age of three years. RESULTS: Overall, 92.5% of hips were mature (Graf types Ia, Ib) at first examination, 7.2% were mature (Graf type IIa) and 0.3% were pathological (Graf types IIc to IV). A total of 146 pathological hips were detected in 118 of newborns (0.6%). Only 0.26% of screened population was treated with an orthosis. The rate of first surgical procedures and the rate of late detected DDH were 0.23 and 0.09 per 1000 live births, respectively. Regarding risk factors, positive family history, female gender, breech presentation, and high birth weight were significantly more common in newborns with pathological hips. CONCLUSION: Early neonatal universal US screening using Graf method is recommended to timely detect DDH and to provide the optimal conservative approach of management. It seems to be effective in reducing the overall treatment rate, together with the rate of surgical procedures and late detected cases.

Interchangeable neck failures of bi-modular femoral stems in primary total hip arthroplasty cannot be predicted from serum trace element analysis.

INTRODUCTION: Revision of a well-fixed stem due to unexpected modular neck fracture is a catastrophe for the patient and a challenge for the surgeon. This study aimed to test the possibility of predicting interchangeable neck fracture from serum levels of the stem/neck alloy-consisting metals. MATERIALS AND METHODS: Nineteen patients at high risk for interchangeable neck fracture were randomly selected out of a cohort of 680 bimodular stems made from Ti6Al4V alloy. Serum levels of titanium, aluminium and vanadium were determined. Nine age- and gender-matched patients were used as controls. RESULTS: Mean serum levels of Ti were 6.04 ± 2.52 µg/L, of Al 3.89 ± 1.68 µg/L and of V 0.07 ± 0.04 µg/L in the high-risk group, and 8.22 ± 4.74 µg/L, 4.99 ± 3.98 µg/L and 0.27 ± 0.44 µg/L in the low-risk group, respectively. No statistically significant differences were found between the groups. DISCUSSION: Interchangeable neck fracture of bimodular femoral stems cannot be predicted from serum trace element analysis.

Lumbar and sacral pedicle screw placement using a template does not improve the midterm pain and disability outcome in comparison with free-hand method.

BACKGROUND: The free-hand technique carries a higher risk of pedicle weakening and neurovascular injuries in comparison with pedicle screw placement using a drill guide. Due to this evidence and because of some variances in the surgical method, different outcome can be expected. The objective of the study was to evaluate the disability, the back and leg pain before and at least 3 years after the surgery between examined groups. MATERIALS AND METHODS: Eleven patients in drill guide and 13 in control group were randomly assigned for vertebral fusion in the lumbar and first sacral regions. Pre- and post-operative CT scans, Oswestry disability index (ODI) and visual analogue scale (VAS) for back and leg pain were taken. Post-operative evaluations of cortex perforation and statistical analysis between studied groups have been performed. RESULTS: Seventy-two screws were inserted in each group. All patients completed a 3-year follow-up. Comparing groups, there was no statistical significant difference in VAS and ODI before or after surgery. Cortex perforation incidence in drill guide group was 6 and in free-hand group 29 (p < 0.05). In each group, pain and disability were significantly lower as before the procedure. CONCLUSIONS: The application of a drill guide template for pedicle screw placement is not more effective in reducing pain and disability after midterm follow-up in comparison with the free-hand technique. However, it reduces the cortex perforation incidence. Concerning this evidence, a drill guide is still an additional tool that could in the future potentially compete with other screw placement techniques.

Error rate of multi-level rapid prototyping trajectories for pedicle screw placement in lumbar and sacral spine.

OBJECTIVE: Free-hand pedicle screw placement has a high incidence of pedicle perforation which can be reduced with fluoroscopy, navigation or an alternative rapid prototyping drill guide template. In our study the error rate of multi-level templates for pedicle screw placement in lumbar and sacral regions was evaluated. METHODS: A case series study was performed on 11 patients. Seventy-two screws were implanted using multi-level drill guide templates manufactured with selective laser sintering. According to the optimal screw direction preoperatively defined, an analysis of screw misplacement was performed. Displacement, deviation and screw length difference were measured. The learning curve was also estimated. RESULTS: Twelve screws (17%) were placed more than 3.125 mm out of its optimal position in the centre of pedicle. The tip of the 16 screws (22%) was misplaced more than 6.25 mm out of the predicted optimal position. According to our predefined goal, 19 screws (26%) were implanted inaccurately. In 10 cases the screw length was selected incorrectly: 1 (1%) screw was too long and 9 (13%) were too short. No clinical signs of neurovascular lesion were observed. Learning curve was insignificantly noticeable (P=0.129). CONCLUSION: In our study, the procedure of manufacturing and applying multi-level drill guide templates has a 26% chance of screw misplacement. However, that rate does not coincide with pedicle perforation incidence and neurovascular injury. These facts along with a comparison to compatible studies make it possible to summarize that multi-level templates are satisfactorily accurate and allow precise screw placement with a clinically irrelevant mistake factor. Therefore templates could potentially represent a useful tool for routine pedicle screw placement.

A multi-level rapid prototyping drill guide template reduces the perforation risk of pedicle screw placement in the lumbar and sacral spine.

INTRODUCTION: The method of free-hand pedicle screw placement is generally safe although it carries potential risks. For this reason, several highly accurate computer-assisted systems were developed and are currently on the market. However, these devices have certain disadvantages. We have developed a method of pedicle screw placement in the lumbar and sacral region using a multi-level drill guide template, created with the rapid prototyping technology and have validated it in a clinical study. The aim of the study was to manufacture and evaluate the accuracy of a multi-level drill guide template for lumbar and first sacral pedicle screw placement and to compare it with the free-hand technique under fluoroscopy supervision. MATERIALS AND METHODS: In 2011 and 2012, a randomized clinical trial was performed on 20 patients. 54 screws were implanted in the trial group using templates and 54 in the control group using the fluoroscopy-supervised free-hand technique. Furthermore, applicability for the first sacral level was tested. Preoperative CT-scans were taken and templates were designed using the selective laser sintering method. Postoperative evaluation and statistical analysis of pedicle violation, displacement, screw length and deviation were performed for both groups. RESULTS: The incidence of cortex perforation was significantly reduced in the template group; likewise, the deviation and displacement level of screws in the sagittal plane. In both groups there was no significantly important difference in deviation and displacement level in the transversal plane as not in pedicle screw length. The results for the first sacral level resembled the main investigated group. CONCLUSIONS: The method significantly lowers the incidence of cortex perforation and is therefore potentially applicable in clinical practice, especially in some selected cases. The applied method, however, carries a potential for errors during manufacturing and practical usage and therefore still requires further improvements.