Equatorial wrinkles in the human lens capsule.

Equatorial wrinkles, or crenations, have been previously observed around the equator in coronal images of the human ocular lens. However, wrinkles are typically not apparent when the lens is viewed from saggital directions. In the current paper, the existence and geometry of these wrinkles is shown to be consistent with a mechanical model of the isolated lens, in which the capsule is held in a state of residual tension by a spatially uniform internal pressure. The occurrence of equatorial wrinkles is therefore seen to be a mechanical consequence of the spheroidal shape of the lens capsule and an excess intralenticular pressure. New observations are made, on post mortem lenses, on the geometric arrangement of these equatorial wrinkles. These observations indicate a well-defined pattern in which wrinkles exists along meridional lines in the equatorial regions of the lens. A preliminary 'puncture test' is used to demonstrate that the residual stresses within the capsule in the equatorial region of the lens are broadly consistent with the proposed mechanical model of the lens capsule. It is suggested that the presence of equatorial wrinkles may have an influence on the mechanical performance of the capsule during the accommodation process.

Transanal TATA/TME: a case-matched study of taTME versus laparoscopic TME surgery for rectal cancer.

BACKGROUND: Natural orifice translumenal endoscopic surgery (NOTES) has always made more sense in the colorectal field where the target organ for entry houses the pathology. To address the question whether an adequate total mesorectal excision (TME) for rectal cancer can be performed from a transanal bottoms-up approach, we performed a case-matched study. METHODS: Starting in 2009, transanal TME (taTME) surgery was selectively used for rectal cancer after neoadjuvant therapy and prospectively entered into a database. Between March 2012 and February 2014, 17 consecutive taTME rectal cancer patients were identified and case-matched to multiport laparoscopic TME (MP TME) based on age, body mass index, uT stage, radiation dose, level in the rectum, and procedure. Perioperative outcomes, morbidity, mortality, local recurrence, completeness of TME, and radial and distal margins were analyzed. Statistically significant differences were identified using Student's t test. RESULTS: There were 12 transanal abdominal transanal (TATA)/5 abdominoperineal resection procedures in each group. Data regarding overall/taTME/MP TME are as follows: % positive-circumferential margin: 2.9/0/5.9 % (p = 0.32). Distal margin: 0/0/0 %. Complete or near-complete TME: 97.1/100/94.1 % (p = 0.32). Incomplete TME 2.9/0/5.9 % (p = 0.32). Local recurrence: 2.9/5.9/0 % (p = 0.32). There were no perioperative mortalities. Morbidity in each group: 26.4/23.5/29.4 % (p = 0.79). There were no differences in perioperative or postoperative outcomes except days to clear liquids (1/2 days, p = 0.03) and largest incision length (1.3/2.6 cm, p = 0.05). CONCLUSIONS: We demonstrated no differences in perioperative/postoperative outcomes or pathologic TME outcomes of transanal or bottoms-up TME compared to standard laparoscopic TME. TaTME is a promising progressive approach to NOTES and deserves additional evaluation.