Accuracy and safety of partial thickness femtosecond laser radial and arcuate keratotomy incisions in porcine eyes

Background To evaluate the accuracy and safety of micro radial and arcuate keratotomy incisions constructed by a femtosecond laser system with a curved contact patient interface in porcine eyes. Methods Partial thickness micro radial and arcuate keratotomy incisions were constructed in porcine eyes with a femtosecond laser system and evaluated for precision of depth, quality, and consistency. Optical coherence tomography was used to determine the accuracy and precision of incision depth. Corneal endothelial safety was assessed by a fluorescent live/dead cell viability assay to demonstrate laser-induced endothelial cell loss. Quality was evaluated by ease of opening and examination of interfaces. Results In two micro radial incision groups, intended incision depths of 50% and 80% resulted in mean achieved depths of 50.01% and 77.69%, respectively. In three arcuate incision groups, intended incision depths of 80%, 600 μm or 100 μm residual uncut bed thickness resulted in mean achieved depths of 80.16%, 603.03 μm and residual bed of 115 μm, respectively. No loss of endothelial cell density occurred when the residual corneal bed was maintained at a minimum of 85–116 µm. The incisions were easy to open, and interfaces were smooth. Conclusions A femtosecond laser system with curved contact interface created precise and reproducible micro radial and arcuate keratotomy incisions. Accuracy and precision of the incision depth and preservation of endothelial cell density demonstrated the effectiveness and safety of the system.

Residual strains estimation in the annulus fibrosus through digital image correlation

Up-to-date, back pain is among the most prevalent health issues and generally takes its origins from lesions of the annulus fibrosus (AF). While the AF ex vivo mechanical properties are increasingly well understood, in vivo data are still missing. In particular, very few studies have precisely measured the residual strains within the AF and thus the in vivo deformation state of the AF is still miss-interpreted and miss-evaluated. In this work, we propose an original and robust method for the AF residual strains quantification via digital image correlation technics. Ten pig annulus fibrosus were extracted from adjacent vertebrae followed by a radial incision to release the residual strains. The operations were filmed and then analyzed by a custom digital image correlation software in order to quantify the circumferential, radial and shear residual deformations. Our results show that residual strains are of the same order of magnitude than the in vivo one. The average circumferential strains are in tension on the outer periphery ([3.32; 5.94]%) and in compression on the inner periphery ([−6.4; −1.69]%). The mean radial residual strains are essentially in compression ([−10.4; 2.29]%). Locally, radial and circumferential residual strains can reach really large values up to 40% of compression. The mean shear strains remain very small (−0.04% ± 2.88%). This study also shows that circumferential and radial residual strains evolve linearly along the radius and non-linearly along the angle. We propose a simple model to predict their spatial variations. Our results and methods will allow the quantification of more realistic in vivo strains and stresses within the human intervertebral disc.

Comparison of Two Conjunctival Incision Techniques in Strabismus Operations: Analysis of the Patient Population in 2008, 2010 – 2014

Background Until 2010, the Halle university hospital used the limbal approach in strabismus operations to open the conjunctiva, as first described by Harms in 1949. In 2010, this was changed the to a modified radial incision technique, as inspired by the fornix incision of Harms and the “minimally invasive strabismus surgery” (MISS) technique of D. S. Mojon. The indication is the reduction in complications and protection of the conjunctiva. Methods A retrospective analysis was performed of cases between 2008 and March 2014 was performed, including a total of 258 patients. 109 patients were treated with the limbal approach and 149 patients with the radial cut. The following aspects were included for comparison: the medium-term control of the squint angle after three months, intra- and postoperative number of complications, duration of the operations. A survey collected the reasons for not taking part in follow-up checks and the alignment of these patients. To compare binary variables, the chi-square-test was used and to compare average terms the unpaired t test, with a level of significance of 0.05%. Results The results of the postoperative square angles were comparable to both each other as to the literature. The number of complications was kept low in both techniques. The duration of the operations under the radial incision technique was clearly higher. However, throughout the observed years the duration of operations turned out to have decreased. The reasons for not taking part in controls were diverse and the alignment of these patients was high, regardless of the incision technique. Conclusions The limbal approach was a well-proven method to open the conjunctiva. After changing to the radial incision technique, there was never a negative influence on the results of the surgeries or the rate of complications. The duration of the operations was extended. Superiority of the new technique was not shown. It could however be an alternative, as it spares the conjunctiva and permits glaucoma operations.

Modified Techniques Versus Hadfield’s Procedure in Patients With Periductal Mastitis

Background: Periductal mastitis (PM) is a rare disease characterized by chronic inflammation of the terminal mammary ducts. Complete removal of the terminal canals with Hadfield’s operation applied in the treatment carries various complication risks. This study is designed to evaluate the effectiveness of modified techniques and compare them with the Hadfield operation.Methods: Twenty women who underwent surgery due to PM between January 2012 and December 2019 were retrospectively analyzed. Types of PM were determined. All patients were operated on with three different incisions (Hadfield’s operation with periareolar incision, periareolar combined with radial incision, and round block incision). Results: The age mean 37.5±6.5 years (range:24-49). Sixty percent of patients had type three PM. For the affected duct excision, a classic Hadfield’s operation with periareolar incision was performed in 11 patients, periareolar incision combined with radial incision was performed in 7 patients. The round block method was performed on two patients. Seroma was observed in only one of the patients who underwent the modified technique. In Hadfield’s procedure, NAC retraction (n:2), seroma (n:1), and hematoma (n:1) were seen. The follow-up period was 12±1.5 months. Recurrence occurred in two patients, and both had Hadfield’s procedures. Conclusions: The main principle of surgical treatment is excision of the affected canal with a clear margin. In PM treatment, The round block method and periareolar incision combined radial incision modifications of the Hadfield procedure reduce complications and recurrence risk.

Radial incision and cutting combined with balloon dilation for refractory pancreaticojejunostomy anastomotic strictures

Background and study aims Endoscopic balloon dilation (BD) and temporary stent placement for pancreaticojejunostomy anastomotic stricture (PJAS) achieves good short-term outcomes; however, stricture recurrences remain frequent. We examined the feasibility of performing radial incision and cutting (RIC) combined with BD for refractory PJAS. Patients and methods Five consecutive patients with refractory PJAS who underwent RIC with BD between 2015 and 2018 were retrospectively investigated. We evaluated the technical and clinical success, adverse event (AE), and recurrence rates associated with RIC with BD. Results In all five patients, technical and clinical success were achieved. Pancreatic stone removal was simultaneously performed in one patient. The mean procedure time was 18 minutes (range 12–23 minutes). There were no procedure-related AEs. All patients were followed for over 2 years, with a mean follow-up period of 33 months (range 24–40 months). During the follow-up period, none of the patients developed stricture recurrence and all anastomoses remained patent. Conclusions This is the first report of RIC with BD for the treatment of refractory PJAS, showing favorable results. This combined procedure might be a useful option for treating refractory PJAS.

A Pilot Study Investigating the Safety and Feasibility of Endoscopic Dilation Using a Radial Incision and Cutting Technique for Benign Strictures of the Small Intestine: A Study Protocol

BackgroundSmall benign intestinal stenosis is usually treated by endoscopic balloon dilation (EBD) or surgery. Although, EBD and surgery are able to resolve the stenosis in most case, they are associated with several problems such as insufficient dilation and surgical stress, respectively. On the contrary, a novel approach called radial incision and cutting (RIC) is reported to have several benefits when compared to EBD and surgery. We can currently adopt RIC only for the strictures in the colon or terminal ileum and not for those stenotic lesions present further in the small intestine where balloon-assisted endoscopy is utilized, because long-type electric knife is currently not approved for use in Japan. We will herein conduct a pilot study to investigate the safety and feasibility of RIC for treating the benign stenoses of the small intestine using the long-type electric knife.Methods This will be a single-center, single-arm, interventional trial. The major criteria for inclusion will be age ranging from 20 to 80 years and the presence of benign stenosis in the small intestine. We will perform RIC in 10 participants. The primary outcome is the safety of this procedure, which will be assessed by measuring the frequency of adverse events of special interest. The secondary outcomes will be technical success rate, improvement in subjective symptoms, procedure time, and duration of hospitalization.DiscussionThis pilot study will provide useful information that will aid in adopting RIC for treating the benign strictures present in the small intestine. Trial registration jRCT Identifier, jRCTs022200040. Registered on 1 March 2021.URL: https://jrct.niph.go.jp/re/reports/detail/11533