A Novel Wax Based Piezo Actuator for Autonomous Deep Anterior Lamellar Keratoplasty (Piezo-DALK)

This paper reports the design and evaluation of a novel piezo based actuator for needle drive in autonomous Deep Anterior Lamellar Keratoplasty (piezo-DALK). The actuator weighs less than 8g and is 20mm × 20mm × 10.5mm in size, making it ideal for eye-mounted applications. Mean open loop positional deviation was 1.17 ± 3.15um, and system repeatability and accuracy were 17.16um and 18.33um, respectively. Stall force was found to vary linearly with the cooling cycle and the actuator achieved a maximum drive force of 3.98N. When simulating the DALK procedure in synthetic corneal tissue, the piezo-DALK achieved a penetration depth of 643.56um which was equivalent to 92.1% of the total corneal thickness. This correlated closely with our desired depth of 90% ± 5% and took 2.5 hours to achieve. This work represents the first eye mountable actuator capable of "Big Bubble" needle drive for autonomous DALK procedures.

Laparoscopic abdominal cerclage after radical vaginal trachelectomy

BACKGROUND

The incidence of cervical cancer (CC) in Slovenia in 2011 was 13.2 per 100,000 women. The treatment of early stages of invasive cervical carcinoma involves several surgical techniques. In this article the authors would like to present a new combination of two methods which help to preserve fertility and to improve pregnancy outcome. The first procedure, radical vaginal trachelectomy (RVT), begins with laparoscopic pelvic lymphadenectomy. All suspicious lymph nodes are sent to frozen section. If those lymph nodes are negative, the procedure continues vaginally. Almost the entire cervix is removed with parametria and vaginal cuff. Permanent cerclage stitch is applied and covered with vagina on what is left of uterus. Second procedure, laparoscopic abdominal cerclage (LAC), begins with pneumoperitoneum. Mersilene tape is introduced in the abdominal cavity and placed through the visceral peritoneum at the isthmic part of the uterus with a Berci's needle. It is knotted and remains permanently.

MATERIALS AND METHODS

For the first procedure all the patients with confirmed cervical carcinoma (FIGO Stage IA₁, IA₂, and IB₁) and with the desire for fertility were recruited. For the second procedure, all the patients after RVT and after miscarriage after 14th week of gestation were recruited.

RESULTS

RVT was performed in 15 patients and laparoscopic abdominal cerclage in three of them (21.5%). All three patients achieved pregnancies and after 36th weeks of gestation delivered by cesarean section (100%).

CONCLUSIONS

RVT alone is an indication for LAC. Considering its success, LAC should be performed before any miscarriage.

Comparison of nerve content in removed parametrial tissue after classic radical hysterectomy and nerve-sparing radical hysterectomy--histologic evaluation

PURPOSE OF INVESTIGATION

The aim of this study was to find whether nerve-sparing radical hysterectomy resulted in a lower amount of nerves in the removed parametrial tissue.

METHODS

Histological specimens from nerve-sparing radical hysterectomy (28 cases) were compared with those obtained after classic radical hysterectomy (26 cases). Width of the parametria and vaginal cuff were measured. Using a point counting technique, nerve areal density was determined in cross sections of resected parametria at 0.5 cm (A), 1 cm (B), 1.5 cm (C) from the cervix.

RESULTS

The width of the resected parametria was smaller in the study group (right side p < 0.013; left side; p < 0.011). The nerve areal density in the lateral part of the right parametrium was lower in the study group (p < 0.01) (Student's t-test). CCONCLUSION: Modified radical hysterectomy is less radical and is nerve-sparing.

[First abdominal access in gynecological laparoscopy: which method to utilize?]

The choice of the technique to enter the peritoneal cavity, during a laparoscopy, depends on a lot of variables which hinder a standardized method and, actually, it appears impossible to show, with certainty, the best method to choose for the first abdominal access in gynecological laparoscopy. The preference for one or another technique depends on the operator experience, school and speciality of the surgeon, laparoscopical upgrading and the work environment; many surgical techniques are not yet used due the limits and fears of some surgeons to change the preference in first access approaching and for the lack of operating versatility by a method or another one. A review of the scientific literature, underlines that the major problems during the first laparoscopical abdominal access are two, vascular and intestinal and their percentage is variable. In this paper we describe the large range of methods for open and closed laparoscopy and for direct access, that permit to perform a first abdominal laparoscopical access, and their major possible problems.

[Stress urinary incontinence: an overview on actual surgical trends]

Stress urinary female incontinence (IUS) is an unpleasant symptom describing a loss of urine during physical exertion; genuine stress incontinence (GSI) is a socially unacceptable, involuntary loss of urine in absence of detrusor activity from the urethra associated with sudden cough or strain. The incidence of IUS is less than 10% in reproductive-age women but may approach 10-20% in postmenopausal women. The IUS pathophysiology is connected with two specific mechanisms: the urethral-bladder sliding out of anatomical area involves the normal system of endobladder/intraabdominal pressures, with a loss of urine; the second mechanism involves the damaged urethral sphincteric function, with a reduction of the urethral closure pressure and a urinary loss after minimal physical stimulation. The IUS medical therapy is troublesome and often inefficient, and the only approved effective measures are the surgical procedures, actually reserved for cases of unsuccessful medical therapy; surgical treatments can be classified according to the access as: vaginal, abdominal, associated and complex. They intend to reposition the urethral-bladder sliding in its normal intra-abdominal position, to allow equal transmission of increased intraabdominal pressure to the bladder and the proximal urethra. In the scientific literature there are more than one hundred surgical procedures for IUS correction, but the IUS surgical approach is anyway the actual gold standard therapy.

Effect of intra-abdominal position of the bladder neck and stability of its supporting structures on pressure transmission ratio after colposuspension

The aim of this prospective study was to evaluate the influence of the higher intra-abdominal position of the bladder neck and the stability of its supporting structures after colposuspension, on pressure transmission to the urethra at the level of the bladder neck. Twenty-eight patients were included in the study. The pressure transmission ratio (PTR) was calculated at the level of the bladder neck, whereas the position and mobility of the bladder neck during coughing were evaluated with perineal ultrasound examination. The measurements were performed before and 3 months after colposuspension. After colposuspension we found a significant elevation of the PTR (P=0.001), a significantly higher intra-abdominal position (P=0.001) and decreased mobility (P=0.001) of the bladder neck during coughing. Also, a negative correlation between the elevation of PTR and decreased mobility of the bladder neck during coughing (r = -0.5049; P = 0.006) and a weak correlation between the elevation of PTR and a higher intra-abdominal position of the bladder neck during coughing were found (r = 0.3828; P=0.044). Reinforced tension resistance of the bladder neck supporting structures seems to be more important than intra-abdominal position of the bladder neck in achieving effective pressure transmission after colposuspension.