Does Surgeon Experience Impact the Risk of Complications After Bernese Periacetabular Osteotomy?

BACKGROUND: Bernese periacetabular osteotomy (PAO) is a technically challenging procedure with potential risk for major complications and a previously reported steep learning curve. However, the impact of contemporary hip preservation fellowships on the learning curve of PAO has not been established. QUESTIONS/PURPOSES: (1) What was the frequency of major complications during the PAO learning curve of two surgeons who recently graduated from hip preservation fellowships? (2) Is increasing level of experience associated with the risk of a complication and with operative time, a possible surrogate measure of surgical performance? METHODS: We retrospectively studied 81 PAOs performed by one of two surgeons who recently graduated from a hip preservation fellowship during their first 4 years of practice in two institutions. One of the surgeons participated as a fellow in 78 PAOs with an increasing level of responsibility during the course of 1 full year. The other surgeon performed 41 PAOs as a fellow during 6 months, also with an increasing level of responsibility during that time. There were 68 (84%) female and 13 (16%) male patients (mean age, 18 years; range, 10-36 years). The frequency of complications was recorded early and at 1 year after surgery and graded according to a validated classification system describing five grades of complications. Complications that required surgical intervention (Grade III) and life-threatening complications (Grade IV) were considered major complications. Persistent pain after surgery, although considered a failure of PAO, was not considered a surgical complication as a result of the multifactorial etiology of pain after hip-preserving surgery. However, early reoperation and revision surgery were counted as complications. To evaluate the association between increasing level of experience and the occurrence of complications, we divided each surgeon's experience into his first 20 procedures (initial interval) and his second 20 (experienced interval) to test whether the incidence of complications or operative time was different between the two intervals. Because the association between experience and the likelihood of a complication was estimated to be consistent between the two surgeons, the analysis was performed with data pooled from the two surgeons. To test whether there was a difference in the likelihood of a complication in the initial and the experienced intervals, a multivariate logistic regression analysis was performed and the adjusted risk of a complication between the two intervals was calculated. Linear regression analyses were used to test the association between surgeon level of experience and operative time. RESULTS: The overall incidence of major (Grade III or Grade IV) complications was 6% (95% confidence interval [CI], 2%-14%). These included deep infection (3% [three of 81]), intraoperative posterior column fracture (1% [one of 81]), and pulmonary embolism (1% [one of 81]). With the numbers available, the risk of a complication did not decrease with increasing surgeon experience. After controlling for body mass index and surgeon, the frequency of a complication did not decrease in the experienced interval relative to the initial interval (odds ratio, 0.78; 95% CI, 0.25-2.4; p = 0.6623). The adjusted risk difference between the experienced interval relative and the initial interval was 6% (95% CI, -11% to 23%). When experience was modeled as a continuous variable (number of PAOs performed), increasing experience was not associated with a lower likelihood of a complication (odds ratio per one PAO increase in experience, 0.99; 95% CI, 0.94-1.04; p = 0.5478). However, after adjusting for body mass index and surgeon, increased experience was associated with a reduction in operative time (slope [change in log operative time per one procedure increase in experience], -0.005; 95% CI, -0.009 to -0.0005; p = 0.0292). For every one additional PAO increase in experience, there was a 0.45% decrease in operative time (95% CI, 0.05%-0.86% decrease]. CONCLUSIONS: With a case exposure greater than 40 PAOs and progressive surgical responsibility during contemporary structured training, two young surgeons were able to perform PAO with a low risk of complications. However, even with that surgical experience before independent practice, surgical time decreased over the first 40 PAOs they performed independently. Our data may help guide orthopaedic residency and hip preservation fellowship programs in establishing training requirements and assessing competency in PAO. LEVEL OF EVIDENCE: Level III, therapeutic study.

Comparison of Different Pulse Modulation Modes for Holmium:Yttrium-Aluminum-Garnet Laser Lithotripsy Ablation in a Benchtop Model.

Introduction: Manipulation of Holmium:Yttrium-Aluminum-Garnet laser parameters such as pulse energy (PE), frequency, and duration can impact laser lithotripsy ablation efficiency. In 2017, Lumenis introduced Moses™ Technology, which uses pulse modulation to enhance the delivery of energy from fiber to stone as well as to minimize stone retropulsion. Since the introduction of Moses Technology, other companies have brought additional pulse modulation concepts to market. The purpose of this in vitro study is to compare the pulse characteristics and stone ablation efficiency of Lumenis Moses Technology with Quanta's Vapor Tunnel™. Materials and Methods: Submerged BegoStone phantoms were systematically ablated using either the Lumenis Moses Pulse 120H or the Quanta Litho 100 clinical laser system. Two PEs (0.4 and 1 J), three fiber-stone standoff distances (SDs) (0.5, 1, 2 mm), and all available pulse duration and modulation modes for each laser were tested in combination. Fiber speed was adjusted to scan across the stone surface at either 1 or 10 pulses/mm to form single pulse craters or an ablation trough, respectively. Volumes of single craters and 1 mm trough segments were imaged and quantified using optical coherence tomography. Results: Ablation volumes decreased with decreasing PE and increasing SD. Statistically significant variability was seen between pulse types (PT) at every tested parameter set. Among pulse modulation modes, Moses Distance (MD) was superior at 0.5 mm in all testing and at 2 mm in trough testing. Vapor Tunnel (VT) was superior in 2 mm single crater testing. All modulated pulses performed similarly at 1 mm. Conclusions: In this benchtop model of laser lithotripsy, stone ablation was significantly impacted by PT. MD demonstrated superior or noninferior stone ablation at most tested parameters. VT maintained its efficacy the best as SD increased. Future work should focus on the mechanistic differences of these modes relative to other traditional laser pulse modes.

Benchtop Assessment of a New Single-Use Flexible Ureteroscope.

Introduction: Single-use flexible ureteroscopes are an increasingly popular alternative to reusable ureteroscopes. In this study, we performed a benchtop examination of the physical and optical properties of the new Dornier Axis™ (Webling, Germany) single-use ureteroscope. Methods: Ten new, never-used Dornier Axis ureteroscopes were assessed for optical performance, maximal tip deflection, and irrigation flow rate with an empty working channel and with insertion of 200 and 365 µm laser fibers, and a 1.9F nitinol basket. All ureteroscopes were then fully deflected 100 times in each direction, and maximal deflection angles were re-measured with and without instruments in the working channel. All measurements were performed in duplicate. In vitro optical testing for resolution, image distortion, and depth of field was performed and compared vs the LithoVue™ (Boston Scientific, Marlborough, MA) single-use ureteroscope. Statistical analyses using paired Wilcoxon rank-sum tests and Kruskal-Wallis multiple-group comparison tests were performed in R. Results: Median maximal deflection angles exceeded 300° in both directions before and after 100 full deflection cycles for all groups except the 365 µm laser fiber group. After 100 deflection cycles, there was no change in the majority of working instruments, except a decrease in upward flexion with an empty channel and 200 µm Moses™ laser fiber, and downward flexion with 200 µm Flexiva™ laser fiber (all <10°). After excluding the 365 µm fiber, there was no difference in multi-group comparison for upward and downward flexion pre- and post-cycling. Median flow rate through an empty channel was 48.0 mL/min, and it decreased significantly with all used instruments (p < 0.001). Compared with the LithoVue, the Axis demonstrated superior resolution at all tested distances and less distortion. Conclusions: The new Dornier Axis single-use ureteroscope demonstrates excellent tip deflection, which remains unchanged after 100 manual flexions in each direction. The Axis also demonstrates superior optical performance compared with the LithoVue in benchtop testing.

Phenotypic divergence among threespine stickleback that differ in nuptial coloration.

By studying systems in their earliest stages of differentiation, we can learn about the evolutionary forces acting within and among populations and how those forces could contribute to reproductive isolation. Such an understanding would help us to better discern and predict how selection leads to the maintenance of multiple morphs within a species, rather than speciation. The postglacial adaptive radiation of the threespine stickleback (Gasterosteus aculeatus) is one of the best-studied cases of evolutionary diversification and rapid, repeated speciation. Following deglaciation, marine stickleback have continually invaded freshwater habitats across the northern hemisphere and established resident populations that diverged innumerable times from their oceanic ancestors. Independent freshwater colonization events have yielded broadly parallel patterns of morphological differences in freshwater and marine stickleback. However, there is also much phenotypic diversity within and among freshwater populations. We studied a lesser-known freshwater "species pair" found in southwest Washington, where male stickleback in numerous locations have lost the ancestral red sexual signal and instead develop black nuptial coloration. We measured phenotypic variation in a suite of traits across sites where red and black stickleback do not overlap in distribution and at one site where they historically co-occurred. We found substantial phenotypic divergence between red and black morphs in noncolor traits including shape and lateral plating, and additionally find evidence that supports the hypothesis of sensory drive as the mechanism responsible for the evolutionary switch in color from red to black. A newly described third "mixed" morph in Connor Creek, Washington, differs in head shape and size from the red and black morphs, and we suggest that their characteristics are most consistent with hybridization between anadromous and freshwater stickleback. These results lay the foundation for future investigation of the underlying genetic basis of this phenotypic divergence as well as the evolutionary processes that may drive, maintain, or limit divergence among morphs.

No difference in outcomes in a matched cohort of operative versus nonoperatively treated displaced medial epicondyle fractures.

The purpose of our study was to compare the treatment outcomes and complications between operatively and nonoperatively treated displaced medial epicondyle fractures. Pediatric patients treated for an acute, displaced medial epicondyle fracture between 2005 and 2015 were retrospectively reviewed. A total of 22 operative participants were matched to 22 nonoperative participants, with an average displacement of 9.7 mm in both groups. There was no statistical difference in average length of immobilization, median time to full pronation/supination and flexion/extension, proportion of patients needing physical therapy, and complications. There were no statistical differences in outcomes between operative and nonoperatively treated, moderately displaced, pediatric medial epicondyle fractures. This suggests that operative and nonoperative interventions show equivalent outcomes for these injuries.