Learning Curves of Laparoscopic Roux-en-Y Gastric Bypass and Sleeve Gastrectomy in Bariatric Surgery: a Systematic Review and Introduction of a Standardization.

BACKGROUND: The most commonly performed bariatric procedures are laparoscopic Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (LSG). Impact of learning curves on operative outcome has been well shown, but the necessary learning curves have not been clearly defined. This study provides a systematic review of the literature and proposes a standardization of phases of learning curves for RYGB and LSG. METHODS: A systematic literature search was performed using PubMed, Web of Science, and CENTRAL databases. All studies specifying a number or range of approaches to characterize the learning curve for RYGB and LSG were selected. RESULTS: A total of 28 publications related to learning curves for 27,770 performed bariatric surgeries were included. Parameters used to determine the learning curve were operative time, complications, conversions, length of stay, and blood loss. Learning curve range was 30-500 (RYGB) and 30-200 operations (LSG) according to different definitions and respective phases of learning curves. Learning phases described the number of procedures necessary to achieve predefined skill levels, such as competency, proficiency, and mastery. CONCLUSIONS: Definitions of learning curves for bariatric surgery are heterogeneous. Introduction of the three skill phases competency, proficiency, and mastery is proposed to provide a standardized definition using multiple outcome variables to enable better comparison in the future. These levels are reached after 30-70, 70-150, and up to 500 RYGB, and after 30-50, 60-100, and 100-200 LSG. Training curricula, previous laparoscopic experience, and high procedure volume are hallmarks for successful outcomes during the learning curve.

Cardiac responses to ß-adrenoceptor stimulation is partly dependent on mitochondrial calcium uniporter activity.

BACKGROUND AND PURPOSE: Despite the importance of mitochondrial Ca(2+) to metabolic regulation and cell physiology, little is known about the mechanisms that regulate Ca(2+) entry into the mitochondria. Accordingly, we established a system to determine the role of the mitochondrial Ca(2+) uniporter in an isolated heart model, at baseline and during increased workload following ß-adrenoceptor stimulation. EXPERIMENTAL APPROACH: Cardiac contractility, oxygen consumption and intracellular Ca(2+) transients were measured in ex vivo perfused murine hearts. Ru360 and spermine were used to modify mitochondrial Ca(2+) uniporter activity. Changes in mitochondrial Ca(2+) content and energetic phosphate metabolite levels were determined. KEY RESULTS: The addition of Ru360 , a selective inhibitor of the mitochondrial Ca(2+) uniporter, induced progressively and sustained negative inotropic effects that were dose-dependent with an EC50 of 7 µM. Treatment with spermine, a uniporter agonist, showed a positive inotropic effect that was blocked by Ru360 . Inotropic stimulation with isoprenaline elevated oxygen consumption (2.7-fold), Ca(2+) -dependent activation of pyruvate dehydrogenase (5-fold) and mitochondrial Ca(2+) content (2.5-fold). However, in Ru360 -treated hearts, this parameter was attenuated. In addition, ß-adrenoceptor stimulation in the presence of Ru360 did not affect intracellular Ca(2+) handling, PKA or Ca(2+) /calmodulin-dependent PK signalling. CONCLUSIONS AND IMPLICATIONS: Inhibition of the mitochondrial Ca(2+) uniporter decreases ß-adrenoceptor response, uncoupling between workload and production of energetic metabolites. Our results support the hypothesis that the coupling of workload and energy supply is partly dependent on mitochondrial Ca(2+) uniporter activity.

Is dissection of level IV necessary in patients with T1-T3 N0 tongue cancer?

OBJECTIVE: Dissection of the lower jugular level of lymph nodes (level IV), as part of an elective neck dissection, has been advocated recently for all patients with oral tongue cancer because of the possibility of "skip metastases" to levels III and IV. The current study was undertaken to evaluate the need to perform a dissection of level IV in patients with oral tongue cancer with no clinical evidence of nodal metastases. METHODS: Fifty-one patients with T1-3, N0 squamous cell carcinoma of the oral tongue were treated with a partial glossectomy and a selective neck dissection of levels I, II, and III. When enlarged nodes were encountered during surgery in level II or III, the dissection was extended to include the nodes in level IV. Involvement of level IV was determined either by the presence of carcinoma on pathological examination or by the development of recurrence in the untreated level IV during a follow-up period of at least 2 years. RESULTS: Level IV was resected as part of the specimen in 17 of the 51 patients and metastatic tumor was found in this level in only one patient. At an average follow-up of 4.1 years, only one patient recurred at level IV, which had been addressed at the initial neck dissection. Consequently, the rate of metastases to undissected level IV was 2%. CONCLUSIONS: Metastases to level IV lymph nodes is rare in patients with T1-T3, N0 oral tongue cancer. Dissection of these nodes only when there is intraoperative suspicion of metastases in levels II or III does not increase the risk or recurrence of tumor in the neck.

Endoscopically assisted "components separation" for closure of abdominal wall defects.

The repair of ventral hernia defects of the abdominal wall challenges both general and plastic surgeons. Ventral herniation is a postoperative complication in 10 percent of abdominal surgeries; the repair of such defects has a recurrence rate as high as 50 percent. The "components separation" technique has successfully decreased the recurrence rates of ventral abdominal hernias. However, this technique has been associated with midline dehiscence and a prolonged postoperative stay at the authors' institutions. The purpose of this study was to determine whether endoscopically assisted components separation could minimize operative damage to the vasculature of the abdominal wall and decrease postoperative wound dehiscence. The study group consisted of seven patients who underwent endoscopically assisted components separation; the control group consisted of 30 patients who underwent open components separation. The two groups were similar regarding demographic data and defect size. The endoscopic group had a higher initial success rate than the open group (100 versus 77 percent). Recurrence rates were not significantly different between the two groups. However, the endoscopically assisted components separation patients had fewer postoperative and long-term complications. In the authors' experience, endoscopically assisted components separation has proved to be a safe and effective method for the repair of complicated and recurrent midline ventral hernias.

A technique for three-dimensional cephalometric analysis as an aid in evaluating changes in the craniofacial skeleton.

A technique is presented for creating a standardized view for use in three-dimensional cephalometry. Three-dimensional cephalometric analysis has become a valuable tool in the assessment of skeletal remodeling, contour changes, and changes in proportion that occur with aging. Computer-assisted tomographic data can be used in either coronal or axial sections; the present study was performed with axially acquired data that was processed in several steps to achieve a standardized position of the facial skeleton for further evaluation. This technique may be a useful adjunct to standard cephalometrics to evaluate the craniofacial skeleton.

Concertina effect and facial aging: nonlinear aspects of youthfulness and skeletal remodeling, and why, perhaps, infants have jowls.

The effect of aging on the orbitomaxillary region is evaluated in the present study. The observation was made that infants look like aged individuals in terms of the midface soft-tissue contours of the midface. Because preliminary work has shown that the facial skeleton remodels throughout life, this observation led to the hypothesis that infants and older individuals appear similar because they have comparable skeletal dimensions, specifically in the orbitomaxillary region. The design is a retrospective analysis of three-dimensional computed tomographic scan data. Three groups of male subjects were studied: infant, ages 1 to 12 months (n = 5); youthful, ages 15 to 24 years (n = 13); and old, ages 53 to 76 years (n = 12). Orbital and zygomaticomaxillary vertical dimensions were measured in both medial and lateral planes between fixed anatomical landmarks. Results were compared by using analysis of variance, Student-Newman-Keuls, and Student's t tests. The findings show that skeletal remodeling is such that the ratio of the maxillary height to orbital height is greatest during youth; during infancy and old age, there is a short maxilla relative to a larger orbit. This finding is significant in the medial plane from orbital rim to pyriform aperture (p < 0.05). Furthermore, there is an actual decrease in vertical maxillary height in this medial plane (p < 0.01) from youth until old age, which occurs secondary to normal skeletal remodeling in the dentate individual. The combined effect of downward expansion of the orbital shelf and the upward migration of the pyriform effectively decreases the space available to support the overlying soft tissues of the midface. An accordion-like or "concertina" effect may lead to compression or restriction of the facial soft tissues over a relatively deficient bony platform. These results highlight the importance of skeletal remodeling in determining the soft-tissue contours of the aging face. The process of skeletal remodeling may also allow for a tentative definition of facial youthfulness. Infants are born with a short maxilla relative to a large orbit, and the maxillary wall is angled posteriorly. This ratio and angle change from infancy until youth, when there is a balance between the bony skeletal support and the overlying soft-tissue envelope, i.e., the skin, facial muscles, and adipose tissue. It is when skeletal remodeling continues past this point that a disharmony occurs. Because the ratio of maxilla/orbit, and the angle of the maxillary wall, in the older person reverts toward that of an infant, the attainment of youth occurs partly in a nonlinear or multimodal manner. This work is part of an emerging concept of facial aging, which we would term an integrated model of facial aging. This model allows facial aging to be viewed as a biological "system," in which there are primary and secondary factors that interact in the process of facial aging. Additional research such as this continues to suggest the importance of bony remodeling in facial aging.

Pyriform augmentation as an ancillary procedure in facial rejuvenation surgery.

A patient is presented in whom augmentation of the pyriform aperture of the maxilla was performed with porous hydroxyapatite in concert with a face and brow lift. Basic research has recently shown that remodeling of the facial skeleton continues throughout life and that this remodeling process leads to changes in the position of several key areas. The pyriform aperture was identified as one region that remodels in a posterior direction, leading to retrusion of the alar base in the older individual. This skeletal retrusion occurs in a very site-specific fashion, and its effects are reflected on the overlying soft tissues of the face. With aging, remodeling of the pyriform aperture posteriorly causes the alar base to appear recessed and decreases the nasolabial angle, changes that are noted on the profile of the older individual. Augmentation of the pyriform aperture can be achieved through a buccal sulcus incision and, when used in conjunction with standard facial rejuvenation procedures, can improve the overall result in facial cosmetic surgery.

Variability of the midfacial muscles: analysis of 50 hemifacial cadaver dissections.

The region of the midface represents a challenging area to both reconstructive and aesthetic surgeons. An anatomic study was performed that attempted to identify patterns and variations of the muscular anatomy. The goals of this study were twofold: to identify patterns and variability of the midfacial muscles that might impact on reconstructive efforts and to attempt to correlate this anatomy with features of the overlying soft tissues, specifically the nasolabial crease. Fifty hemifacial cadaver dissections were performed. The information collected was assembled into a large data base, and statistical significance was analyzed using Fisher's exact probability test. Results demonstrated that, although a great degree of variability exists with respect to the midfacial muscles, seven distinct patterns of these muscles did emerge. The most common pattern was the presence of a levator alae nasi, levator labii superioris, and zygomaticus major, which occurred in 44 percent of specimens. Specimens that possessed a risorius, zygomaticus minor, or both, were relatively uncommon. The consistent presence of the levators suggests adding a superior vector to recreate a smile in facial reanimation surgery. Two important anatomic variations were noted. A bifid zygomaticus major was found to be present in 34 percent of individuals. Because the inferior bundle had a dermocutaneous insertion, this anomaly may represent the anatomic correlate of a cheek "dimple." A second anomaly noted was the lateral cheek crease, which appeared to be associated with a cutaneous attachment from the underlying platysma muscle. However, no correlation could be found for facial muscle pattern and the overlying nasolabial crease structure. This lack of correlation may indicate that the facial muscles alone do not dictate the structure of the nasolabial crease and that other dynamic factors are involved in determining this feature of the aging face.

Double or bifid zygomaticus major muscle: anatomy, incidence, and clinical correlation.

The anatomy of the double or bifid zygomaticus major muscle is investigated in a series of 50 hemifacial cadaver dissections. The double zygomaticus major muscle represents an anatomical variation of this muscle of facial expression. This bifid muscle originates as a single structure from the zygomatic bone. As it travels anteriorly, it then divides at the sub-zygomatic hollow into superior and inferior muscle bundles. The superior bundle inserts at the usual position above the comer of the mouth. The inferior bundle inserts into the modiolus below the corner of the mouth. The incidence of the double zygomaticus major muscle was 34% in the present study, as it was found to be present in 17 of 50 cadaver dissections. This study shows that variation in the individual morphology of the mimetic muscles can be a common finding. Clinically, the double or bifid zygomaticus major muscle may explain the formation of cheek "dimples." The inferior bundle was observed in several specimens to have a dermal attachment along its mid-portion, which tethers the overlying skin. When an individual with this anatomy smiles, traction on the skin may create a dimple due to this dermal tethering effect.

Relative maxillary retrusion as a natural consequence of aging: combining skeletal and soft-tissue changes into an integrated model of midfacial aging.

The contribution of maxillary retrusion to the formation of the nasolabial fold is evaluated in the present study. Clinical observation of patients from the craniofacial unit with concomitant maxillary retrusion revealed prominent signs of midfacial aging: specifically these individuals displayed a prominent nasolabial fold at an early age. This observation led to the hypothesis that relative maxillary retrusion occurs as a normal feature of the aging process. Retrusion of the lower facial skeleton below the soft tissue of the nasolabial fold causes the nasolabial fold to appear more prominent. To test this hypothesis, computed tomographic data were assembled retrospectively and included both males and females, young and old. The age range of the males (n = 14) was 18 to 24 years (young) and 43 to 57 years (old); the age range of the females (n = 14) was 15 to 30 years (young) and 43 to 57 years (old). All individuals had complete upper dentition and had no bony facial injury. Computed tomographic data were reconstructed into three-dimensional images, and a technique was developed to create a standardized lateral view which eliminated rotational variance. Analysis of anterior-posterior changes showed that there is a tendency for the lower maxillary skeleton at pyriform to become retrusive with age relative to the upper face in individuals with complete dentition. Findings were very significant for both males and females (p = 0.0001 and p = 0.002, respectively). In both groups, a slight increase in vertical maxillary dimension was noted, consistent with previous studies. It is suggested that relative maxillary retrusion is a factor in the development of the nasolabial fold. The skeletal features of normal midfacial aging can be combined with the soft-tissue features such as ptosis and atrophy into an integrated model of midfacial aging. A model such as this has significance regarding both the timing and choice of procedure used to restore the aging midface.

Anatomy of a "black eye": a newly described fascial system of the lower eyelid.

The anatomy of a black eye is examined in a series of cadaver dissections in which a previously unreported fascial system of the lower eyelid is identified. This fascia originates at the orbital rim, and is in continuity with the orbital septum and with the periosteum of the orbital floor and anterior maxillary wall. This fascia contributes to the thickened area along the orbital rim called the arcus marginale. At the level of the orbicularis oculi muscle, this fascia was noted microscopically to fuse with a fibrous septa of the superficial cheek fat. This creates one long continuous membrane from the orbital rim above to the cheek skin below. Dye injection techniques show that this membrane is impermeable and traps injected dye in the same place where a black eye forms. After periorbital injury, extravasated hemoglobin pigment is confined to the area above the cutaneous insertion of this membrane. This fascial system has been named the septum malaris: malar describes its origin along the orbital rim of the cheek, and septum further describes the partitioning nature of this ultra-thin membrane.

The anatomy of the labiomandibular fold.

The anatomy of the labiomandibular fold was evaluated in a series of 12 fresh hemifacial cadaver dissections. The techniques of methylene blue dye injection, histologic evaluation, and gross dissection all confirm that the labiomandibular fold has distinct anatomic boundaries. The superior boundary is formed by the cutaneous insertion of the depressor anguli oris muscle at the labiomandibular crease. The inferior boundary is determined by the mandibular ligament, which has been previously described. The cutaneous insertion of the depressor muscle and the mandibular ligament act as relative points of fixation. The dynamic forces of both aging and facial animation act about these two points to create the typical appearance of the labiomandibular fold. This anatomy is consistent with that seen in other areas of the face such as the nasolabial and nasojugal folds, where the dermal insertion of muscle and/or fascia defines an anatomically distinct region. Clinically, this anatomy may suggest that a subcutaneous plane of dissection during the face lift procedure may allow manipulation and reduction of the fat that was noted lateral to the dermal insertion of the depressor anguli muscle. Subcutaneous dissection also avoids lateral pull on the platysma muscle, which may tend to accentuate and distort the labiomandibular crease due to its intimate association with the overlying depressor muscle.

The malar septum: the anatomic basis of malar mounds and malar edema.

The anatomy of malar mounds and malar edema is evaluated in a series of 18 fresh cadaver dissections. Dye injection, histologic evaluation, and gross anatomic dissection are used to identify a previously unrecognized fascial structure of the lower eyelid and cheek. The malar septum originates from orbital rim periosteum superiorly and inserts into cheek skin 2.5 to 3 cm inferior to the lateral canthus. This fascial structure acts as a relatively impermeable barrier that allows tissue edema and hemoglobin pigment to accumulate above its cutaneous insertion. The malar septum, which acts as both a functional and a structural barrier, defines the lower boundary of several clinical entities: malar mounds, malar edema, malar festoons, and periorbital ecchymosis. The permeability characteristics of the malar septum suggest that, at least in some persons, malar mounds may be accentuated by chronic lower eyelid edema, and these characteristics may imply a time course in the progressive development from malar edema to malar mounds and, ultimately, to malar festoons. The anatomy of the malar septum is clinically relevant because it defines the four anatomic compartments of the malar mound that should be considered during surgery: the superior compartment of suborbicularis oculi fat, orbicularis oculi muscle, and superficial cheek fat and cheek skin superior to the cutaneous insertion of the malar septum.

Use of double gloves to protect the surgeon from blood contact during aesthetic procedures.

The potential for blood contact with nonintact skin puts operating room personnel at an increased risk of exposure to hepatitis or HIV virus. Frank needle-stick injury to the surgeon has been shown to occur once every 20-40 operations. It has been shown that blood contact exposure during aesthetic surgery occurs in 32% of the operations in which a single pair of surgical gloves is used (surgeon 39.7%, assistant 23%). The reduction of blood contact exposure during aesthetic surgical procedures by using two pairs of gloves was tested and demonstrated. Contact rates decreased by 70%. Outer-glove perforations occurred in 25.6% of the cases, while inner-glove perforations occurred in only 10% of the cases (surgeon 8.7%, assistant 3.5%). All of the inner-glove perforations occurred during procedures that lasted longer than two hours, and in no case was there an inner-glove defect without a corresponding outer-glove perforation. The nondominant index finger (33%) was the most common location. Double gloving during aesthetic procedures reduced the operating room personnel's risk of blood contact exposure by 70% when compared with single-glove use.

Impact tolerances of the rigidly fixated maxillofacial skeleton.

A study was designed to determine how soon an athlete who undergoes rigid fixation of a facial fracture can return to full competition. The impact resistance of a rigidly fixated malar complex fracture was studied and compared with that of an intact malar complex. Twelve fresh human cadaver heads were used. A custom-designed impact device was used to deliver a blow of a specific energy to each intact malar complex. The subsequent fractures were rigidly fixated at three points using titanium miniplates and screws. A second impact of identical energy was delivered. The forces generated and the subsequent displacement of hard and soft tissues were recorded after each impact. It was concluded from this study that an impact to a rigidly fixated malar complex fracture produced less force and greater displacement of hard and soft tissues than an impact of identical energy to an intact malar complex. The potential for sustaining more severe maxillofacial injuries after an initial facial fracture should be seriously considered. The results suggest that sufficient time should be allowed for the bony healing of a facial fracture to occur, even after rigid fixation, before an athlete can resume full contact activities.

Baseline motility of the free jejunal graft in a new canine model.

Reconstruction of pharyngoesophageal defects using free jejunal grafts has become an accepted technique of reconstruction. However, there are functional problems associated with the jejunal graft. We developed a canine model that allows us easy access to perform various studies on grafted jejunum, including videofluoroscopy and pressure manometry to determine baseline function. Using a microvascular technique, free jejunal grafts 10 to 30 cm in length were implanted in 11 mongrel dogs. The jejunal segments were implanted subcutaneously and exteriorized proximally and distally. The grafted dogs underwent videofluoroscopic studies. These studies revealed three different types of jejunal graft contractions of variable intensity: circumferential, longitudinal, and mixed. These contractions resulted in four patterns of barium movement: anterograde propulsion, retrograde propulsion, to-and-fro motion, and peristaltic propulsion. Videofluoroscopic studies were repeated on five dogs after an intravenous injection of metoclopramide (Reglan), which caused a significant short-term increase in the intensity of the basic jejunal contractions and barium propulsion. Pressure manometry studies using intraluminal pressure transducers were performed, revealing an inherent baseline contractility. Each dog has its own individual pattern of activity. The pressure generated by the contractions ranged from 5 to 350 mm Hg. Intravenous injection of Reglan produced a marked increase in pressure, but no change in the frequency of contractions. This study suggests that a free jejunal graft will maintain baseline motility. However, this graft may cause dysphagia by discoordination of contractions, retrograde propulsion of a bolus, or a sustained local contraction, demonstrating the clinical problems associated with free jejunal graft reconstruction of the cervical esophagus. Our results with Reglan suggest that it might be possible to improve the function of these grafts using pharmacologic agents.

Zygote intrafallopian transfer as a treatment for nontubal infertility: a 2-year study.

Zygote intrafallopian transfer (ZIFT) was used as a treatment for long-standing nontubal infertility for a 2-year period. The overall clinical pregnancy rate for 114 tubal transfers was 40.4% with a delivery/ongoing rate of 34.2%. Concurrent use of in vitro fertilization and embryo transfer (IVF-ET) for tubal factor infertility gave significantly lower clinical pregnancy and delivery/ongoing rates (21.1% and 15.8%, respectively). The use of gamete intrafallopian transfer (GIFT) for nontubal infertility yielded a 32% clinical pregnancy rate and a 26% delivery rate for 53 transfers. Zygote intrafallopian transfer resulted in an implantation rate per zygote of 17% overall compared with 8.1% per embryo for IVF-ET and 11.2% per oocyte for GIFT. The transfer of three zygotes per patient gave the same clinical pregnancy rate as the transfer of four while reducing the incidence of multiple gestation from 19% to 7.8% per transfer. No significant decline in the clinical pregnancy or delivery rate was seen with ZIFT in women aged 25 through 39.

New canine model for free jejunal graft studies.

The need to more fully understand the function and physiology of the free jejunal graft prompted us to develop a new canine model. Twelve dogs were used to transplant a free jejunal graft in the neck with proximal and distal stomas exteriorized to the skin. The techniques used, complications encountered, and the potential for acute and chronic studies with this animal model are presented.

Characterization of ornithine decarboxylase activity in human uterine decidua vera.

Ornithine decarboxylase (ODC) catalyzes the rate-limiting step in the biosynthesis of the polyamines putrescine, spermidine, and spermine. In the present study, we characterized the activity of ODC in human uterine decidua vera tissue. We evaluated the activity of the enzyme in decidua vera tissue that was obtained from pregnancies at term before or after the spontaneous onset of labor and in decidua vera tissue that was obtained between 8 and 18 weeks' postconceptional gestational age at the time of elective abortion. Among these tissues, no significant differences in ODC activity were demonstrable.