Tendon Adhesions: A Novel Method of Objectively Measuring Adhesions by Assessing Tendon Glide Through a Soft Tissue Envelope in a Rat Model.

PURPOSE: To develop a rat model of extra-synovial tendon adhesions that will enable accurate testing of scar barriers and adhesion inhibiting treatments to facilitate future research. METHODS: Thirty-six 6-month-old male Sprague-Dawley rats were randomized to one of the 3 groups of 12. In Group A, the middle one-third portion of the left Achilles tendon was excised. In Group B, the tendon and soft tissue bed was abraded with steel wool. In Group C, a silk suture was sewn along the tendon. The right hind limbs served as controls. At 4 weeks, biomechanical testing was performed on the bilateral hind limbs. The Achilles tendon was cut at the gastrocnemius-tendon junction proximal to the "adhesion zone" (or analogous level in the control limb). The calcaneal insertion of the Achilles was attached to a tensiometer. The force needed to pull the tendon out of its soft tissue envelope at a fixed rate was measured. RESULTS: Three rats were excluded because of complications during data collection. Pair-wise comparison testing was performed, comparing the mean peak force to pull the Achilles tendon from its soft tissue envelope in 33 control limbs and the contralateral limb from each group. The average peak force for the cut tendon group (A) was 20.1 N, 18.8 N in the steel wool group (B), and 21.1 N in the suture group (C). The average peak force in the control limbs was 15.6 N. There was a significant difference noted in peak forces between the control limbs and each experimental group. CONCLUSIONS: A consistent and statistically increased force was necessary to pull a rodent Achilles tendon from an adhesion-induced tissue bed compared with controls. No statistical difference was detected between experimental groups. CLINICAL RELEVANCE: Our study demonstrates an objective method of biomechanical tendon adhesion assessment in a rat model.

Porcine acellular dermal matrix (PADM) vascularises after exposure in open necrotic wounds seen after complex hernia repair.

Biological alternatives to synthetic meshes are increasingly utilised in complex abdominal wall reconstruction. There is a lack of evidence demonstrating that non-cross-linked porcine acellular dermal matrix vascularizes and integrates with human tissue in suboptimal wound conditions. We aimed to evaluate these properties in Strattice™ (Life Cell Inc., Branchburg, NJ) following ventral hernia repair. A retrospective review of patients with high-risk ventral hernia repair utilising Strattice™ as an onlay after open component separation was conducted. Patients with postoperative wound exploration and exposure of the onlay were included in this review. One patient underwent punch biopsy for histological analysis. Eleven patients with wound complications necessitating postoperative debridement and exposure of Strattice™ onlay were identified. The onlay was partially debrided in two cases, and one case required complete excision. Vascularisation was clinically evident in 10 of 11 cases (91%) as demonstrated by the presence of granulation tissue and/or the ability to support a skin graft. Histological analysis of one onlay 3 months postoperatively showed neovascularisation and collagen remodelling with minimal inflammatory response. Strattice™ demonstrated resistance to rejection, ability to undergo vascularisation and incorporation into host tissues in sub-optimal wound conditions following ventral hernia repair.

A modified approach to component separation using biologic graft as a load-sharing onlay reinforcement for the repair of complex ventral hernia.

BACKGROUND: Components separation has been proposed as a means to close large ventral hernia without undue tension. We report a modification on open components separation that allows for the incorporation of onlaid noncrosslinked porcine acellular dermal matrix (Strattice, LifeCell Corp, Branchburg, NJ) as a load-sharing structure. METHODS: This was a retrospective case series including all cases using Strattice from July 2008 through December 2009. Data evaluated included patient demographics, comorbidities associated with risk of recurrence, hernia grade, and postoperative complications. The primary outcomes were hernia recurrence and surgical site occurrences. RESULTS: There were 58 patients; 60.8% presented with a recurrent incisional hernia. Average length of follow-up was 384 days. There were 4 hernia recurrences (7.9%). Complications included surgical site infection (20.7%), seroma (15.5%), and hematoma (5%) requiring intervention. Four deaths occurred in the series due to causes unrelated to the hernia repair, only 1 within 30 days of operation. CONCLUSIONS: This series demonstrates that components separation reinforced with noncrosslinked porcine acellular dermal matrix onlay is an efficacious, single-stage repair with a low rate of recurrence and surgical site occurrences.

Pectoralis major turnover versus advancement technique for sternal wound reconstruction.

BACKGROUND: We compared the efficacy of pectoralis turnover versus advancement technique for sternal wound reconstruction. METHODS: A retrospective chart review was performed, December 1989 to December 2010, to compare postoperative complication rates between pectoralis major turnover versus pectoralis major advancement reconstruction techniques. Complications included hematomas, wound infections, tissue necrosis, dehiscence, and need for reoperation. Pearson χ and logistic regression were used and significance was P < 0.05. RESULTS: Sixty-seven patients received 91 tissue flaps. Eleven patients (16%) required reoperation due to complications, including recurrent wound infection, tissue necrosis, wound dehiscence, mediastinitis, and hematoma formation. Four patients (6%) were treated conservatively for minor complications. Overall, complication rates were significantly higher after pectoralis major advancement reconstruction (32.5% vs. 3.7%, P = 0.004). CONCLUSIONS: When feasible, pectoralis major turnover flap offers a superior reconstructive technique for complex sternal wounds, with diminished complications compared with the pectoralis advancement flap.

Transoral submucosal resection of the inferior turbinate: a novel approach to functional rhinoplasty.

BACKGROUND: In the presence of turbinate dysfunction, an inferior turbinectomy for persistent hypertrophy of bone and/or mucosa may be performed. We sought to explore anatomic feasibility of a transoral turbinectomy. METHODS: After transoral inferior turbinectomy in 12 cadavers, average distances from the external nasal valve to inferior turbinate and from pyriform aperture to inferior turbinate were compared. Average "area of access" was calculated. Preoperative and postoperative nasal length, tip projection, and alar-base width were also compared. RESULTS: Average distance from external nasal valve to inferior turbinate was 32.4 mm. Average distance from aperture to inferior turbinate was 2.4 mm (P < 0.0001). Average "areas of access" to nasal vault through the external nasal valve and mouth were 183.9 mm(2) and 243.6 mm(2) (P = 0.07), respectively. CONCLUSIONS: The transoral approach provides a larger "area of access" to the turbinate, a statistically significant reduction of distance to target, no postoperative changes in nasal soft tissue, and easier instrumentation.

Prevention of 3 "never events" in the operating room: fires, gossypiboma, and wrong-site surgery.

BACKGROUND: This study sought to identify and provide preventative recommendations for potentially devastating safety violations in the operating room. METHODS: A Medline database search from 1950 to current using the terms patient safety and operating room was conducted. All topics identified were reviewed. Three patient safety violations with potential for immediate and devastating outcomes were selected for discussion using evidence-based literature. RESULTS: The search identified 2851 articles, 807 of which were directly related to patient safety in the operating room. Topics addressed by these 807 included infectious complications (26%), fires (11%), communication/teamwork (6%), retained foreign objects (3%), safety checklists (1%), and wrong-site surgery (1%). Fires, gossypiboma, and wrong-site surgery were selected for discussion. CONCLUSIONS: Although fire, gossypiboma, and wrong-site surgery should be "never events" in the operating room, they continue to persist as 3 common patient safety violations. This study provides the epidemiology, common etiologies, and evidence-based preventative recommendations for each.

The sentinel fat pads: the relationship of the ROOF and SOOF to the temporal nerve in facial rejuvenation.

BACKGROUND: A great number of studies have reported on the temporal branch anatomy and its relationship to the fascial layers and various fat pads of the temporal region, but no article has included information on the relationship of the temporal nerve to the retro-orbicularis oculi fat (ROOF) and/or the suborbicularis oculi fat (SOOF). OBJECTIVES: The authors report the results of a series of human cadaver temporal nerve dissections, with particular attention paid to its relation to the ROOF and the SOOF. The results of a literature review and a subsequent open browlift are also reported to confirm the results of the cadaver study. METHODS: Dissection was performed on 15 fresh human cadavers, for a total of 29 hemifaces. The course and relationships of the temporal nerve branch to the fascia, fat pads, and landmarks in the temporal region were noted and detailed. A thorough review was also performed for 23 articles, to compare the author's anatomical findings with data in the previous literature. RESULTS: During cadaver dissection, the temporal branch was found to lie on the undersurface of the superficial temporal fascia. In the supraorbital area, the ROOF existed in the loose areolar plane or deep layer of the superficial temporal fascia, with the temporal nerve branch directly superficial to it. The temporal branch passed lateral to the SOOF in its superiomedial course at the level of the zygoma. These findings were later confirmed during an in vivo open browlift as well. CONCLUSIONS: The ROOF was formerly unrecognized as an important sentinel marker for possible injury to the temporal nerve branch during browlift. However, this cadaver study and its accompanying literature comparisons show that browlift dissection, whether endoscopic or open, should aim to keep the ROOF fat in the superficial plane, ensuring that the nerve branch is safe from iatrogenic injury.

Characterization of quinolinate synthases from Escherichia coli, Mycobacterium tuberculosis, and Pyrococcus horikoshii indicates that [4Fe-4S] clusters are common cofactors throughout this class of enzymes.

Quinolinate synthase (NadA) catalyzes a unique condensation reaction between iminoaspartate and dihydroxyacetone phosphate, affording quinolinic acid, a central intermediate in the biosynthesis of nicotinamide adenine dinucleotide (NAD). Iminoaspartate is generated via the action of l-aspartate oxidase (NadB), which catalyzes the first step in the biosynthesis of NAD in most prokaryotes. NadA from Escherichia coli was hypothesized to contain an iron-sulfur cluster as early as 1991, because of its observed labile activity, especially in the presence of hyperbaric oxygen, and because its primary structure contained a CXXCXXC motif, which is commonly found in the [4Fe-4S] ferredoxin class of iron-sulfur (Fe/S) proteins. Indeed, using analytical methods in concert with Mossbauer and electron paramagnetic resonance spectroscopies, the protein was later shown to harbor a [4Fe-4S] cluster. Recently, the X-ray structure of NadA from Pyrococcus horikoshii was solved to 2.0 A resolution [Sakuraba, H., Tsuge, H.,Yoneda, K., Katunuma, N., and Ohshima, T. (2005) J. Biol. Chem. 280, 26645-26648]. This protein does not contain a CXXCXXC motif, and no Fe/S cluster was observed in the structure or even mentioned in the report. Moreover, rates of quinolinic acid production were reported to be 2.2 micromol min (-1) mg (-1), significantly greater than that of E. coli NadA containing an Fe/S cluster (0.10 micromol min (-1) mg (-1)), suggesting that the [4Fe-4S] cluster of E. coli NadA may not be necessary for catalysis. In the study described herein, nadA genes from both Mycobacterium tuberculosis and Pyrococcus horikoshii were cloned, and their protein products shown to contain [4Fe-4S] clusters that are absolutely required for activity despite the absence of a CXXCXXC motif in their primary structures. Moreover, E. coli NadA, which contains nine cysteine residues, is shown to require only three for turnover (C113, C200, and C297), of which only C297 resides in the CXXCXXC motif. These results are consistent with a bioinformatics analysis of NadA sequences, which indicates that three cysteines are strictly conserved across all species. This study concludes that all currently annotated quinolinate synthases harbor a [4Fe-4S] cluster, that the crystal structure reported by Sakuraba et al. does not accurately represent the active site of the protein, and that the "activity" reported does not correspond to quinolinate formation.

Radiographic markers of femoroacetabular impingement: correlation of herniation pit and femoral bump with a positive cross-over ratio.

Introduction. The goal of this study was to research the association of femoral bumps and herniation pits with the overlap-ratio of the cross-over sign. Methods. Pelvic X-rays and CT-scans of 2925 patients with good assessment of the anterior and the posterior acetabular wall and absence of neutral pelvic tilt were enrolled in the investigation. Finally pelvic X-rays were assessed for the presence of a positive cross-over sign, and CT-scans for a femoral bump or a herniation pit. Additionally, if a positive cross-over sign was discovered, the overlap-ratio was calculated. Results. A femoral bump was found in 53.3% (n = 1559), and a herniation pit in 27.2% (n = 796) of all hips. The overlap-ratio correlated positively with the presence of a femoral bump, while a negative correlation between the overlap-ratio and the presence of a herniation pit was found. The latter was significantly more often combined with a femoral bump than without. Conclusions. We detected an increased prevalence of femoral bump with increasing overlap-ratios of the cross-over sign indicating a relation to biomechanical stress. The observed decreased prevalence of herniation pits with increasing overlap-ratios could be explained by reduced mechanical stress due to nontightened iliofemoral ligament in the presence of retroversion of the acetabulum.

Poland syndrome with extracorporeal intercostal liver herniation and thoracic myelomeningocele.

Poland syndrome is characterized by hypoplastic unilateral chest wall structures. These chest wall deformities may be associated with upper extremity anomalies. The association of Poland syndrome with either intercostal liver herniation or a spinocerebral deformity has been described, but there is no report of both findings encountered simultaneously. This is the first report of a newborn child with Poland syndrome associated with an intercostal liver segment herniation and thoracic myelomeningocele with features of an Arnold-Chiari II cerebral malformation.

Z-mammaplasty: a novel concept in mastopexy.

BACKGROUND: The inverted-T technique is the most popular skin pattern used for mastopexy, but short scar variations have increased in popularity over recent years. With respect to nipple elevation, superior, superomedial, medial, inferior, lateral, and central pedicle designs have been described. OBJECTIVES: We introduce a novel concept for mastopexy, the glandular Z-mammaplasty, and assess its anatomic and technical feasibility. METHODS: Glandular Z-plasty was performed on 15 human female cadavers. Various parameters were measured pre- and postoperatively to assess degree of ptosis and subsequently compared by student t test. RESULTS: Average pre and postoperative breast width (28.5 ± 4.7 cm, 26.7 ± 3.2 cm, P = .009), breast length (25 ± 6.6 cm and 21.8 ± 4.3 cm P = .005), breast height (10.7 ± 3.7 cm and 9.5 ± 2.9 cm, P = .02), and ptosis degree (1.9 ± 0.9 cm and 0.3 ± 0.5 cm, P < .0001) were determined. Inferior limb transposition moved the nipple closer to the sternal notch and sternum midline an average of 5.3 ± 2.2 cm and 2.4 ± 1.7 cm, respectively. The average Z-plasty degree was 34.5 ± 8.2°. The average central limb length was 8.7 ± 2.1, and the average pedicle width was 5.4 ± 0.8 cm. Buttress support of the nipple was accomplished by caudal transposition of the superior Z-plasty flap and its inset below the nipple. CONCLUSION: We demonstrate that glandular Z-mammaplasty is indeed feasible. The grade of ptosis was statistically significantly improved, with the nipple moving superiorly an average of 5.3 cm in our study group.

The activity of Escherichia coli cyclopropane fatty acid synthase depends on the presence of bicarbonate.

Cyclopropane fatty acid (CFA) synthases catalyze the formation of cyclopropane rings on isolated and unactivated olefinic bonds within various fatty acids; the methylene carbon is derived from the activated methyl group of (S)-adenosylmethionine. The E. coli enzyme is the prototype for this class of enzymes, which include the cyclopropane mycolic acid (CMA) synthases, which are potential targets for the design of antituberculosis agents. Crystal structures of several CMA synthases have recently been solved, and electron density attributed to a bicarbonate ion was found in or near the active site. Because a functional assay for CMA synthases has not been developed, the relevance of the bicarbonate ion has not been established. CFA synthase is 30-35% identical to the CMA synthases that have been analyzed structurally, suggesting that the mechanisms of these enzymes are conserved. In this work, we show that indeed the activity of CFA synthase requires bicarbonate, and that it is inhibited by borate, a planar trigonal molecule that mimics the structure of bicarbonate. We also show that substitutions of the conserved amino acids that act as ligands to the bicarbonate ion based on the structure of CMA synthases result in drastic losses in the activity of the protein.

Escherichia coli quinolinate synthetase does indeed harbor a [4Fe-4S] cluster.

Quinolinic acid is an intermediate in the biosynthesis of nicotinamide-containing redox cofactors. The ultimate step in the formation of quinolinic acid in prokaryotes is the condensation of iminosuccinate and dihydroxyacetone phosphate, which is catalyzed by the product of the nadA gene in Escherichia coli. A combination of UV-vis, Mössbauer, and EPR spectroscopies, along with analytical methods for the determination of iron and sulfide, demonstrates for the first time that anaerobically purified quinolinate synthetase (NadA) from E. coli contains one [4Fe-4S] cluster per polypeptide. The protein is active, catalyzing the formation of quinolinic acid with a Vmax [ET]-1 of 0.01 s-1.