Preventing pancreatic fistula after distal pancreatectomy: An invagination method.

Following an increase in the use of the GIA stapler for treating a pancreatic stump, more techniques to prevent postoperative pancreatic juice leakage have been required. We describe one successful case using our new technique of invaginating the cut end of the pancreas into the stomach to prevent a pancreatic fistula (PF) from occurring. A 50-year-old woman with pancreatic cancer in the tail of the pancreas underwent distal pancreatectomy, causing a grade A PF. We resected the distal pancreas without additional reinforcement to invaginate the stump into the gastric posterior wall with single layer anastomosis using a 3-0 absorbable suture. The drain tubes were removed on the third postoperative day. Although a grade A PF was noted, the patient was discharged on foot on the eleventh postoperative day. Our technique may be a suitable method for patients with a pancreatic body and tail tumor.

Efficacy of transversus abdominis plane block and rectus sheath block in laparoscopic inguinal hernia surgery.

We aimed to assess the efficacy of transversus abdominis plane (TAP) block and rectus sheath (RS) block in patients undergoing laparoscopic inguinal hernia surgery. Few studies have addressed the efficacy and safety associated with TAP block and RS block for laparoscopic surgery. Thirty-two patients underwent laparoscopic inguinal hernia surgery, either with TAP and RS block (Block(+) group, n = 18) or without peripheral nerve block (Block(-) group, n = 14). Preoperatively, TAP and RS block were performed through ultrasound guidance. We evaluated postoperative pain control and patient outcomes. The mean postoperative hospital stays were 1.56 days (Block+ group) and 2.07 days (Block(-) group; range, 1-3 days in both groups; P = 0.0038). A total of 11 patients and 1 patient underwent day surgery in the Block(+) and Block(-) groups, respectively (P = 0.0012). Good postoperative pain control was more commonly observed in the Block(+) group than in the Block(-) group (P = 0.011). TAP and RS block was effective in reducing postoperative pain and was associated with a fast recovery in patients undergoing laparoscopic inguinal hernia surgery.

Regeneration of central nervous tissue using a collagen scaffold and adipose-derived stromal cells.

Adipose-derived stromal cells (ASCs) include stem cells, which have the potential to differentiate into a variety of cell lineages. The regeneration of central nerves was examined using ASCs and a collagen scaffold. A cerebral cortex defect (3 x 4 x 3 mm(3)) was created in the left frontal lobe of 16 male rats. In one group (n = 8), collagen (3 x 4 x 3 mm(3)) seeded with DiI-labeled ASCs was implanted in the defect. In order to seed the ASCs, a combination of the rotary cell culture system and pressing the collagen scaffold gently several times with a glass rod was applied. In the control group (n = 8), collagen was implanted without ASCs. The rats were sacrificed at 1 month after the scaffold implantation. Histologically, 0.2% of the implanted ASCs were positive for anti-human/rat microtubule-associated protein 2 (MAP2) antibody and microvessels were present at a density of 4.6 +/- 1.2/mm(2) within the collagen scaffold-implanted area in each coronal section. In the control group, no MAP2-positive cells were detected and the microvessel density was 0.6 +/- 0.4/mm(2). These data suggest that ASCs seeded into a collagen scaffold may have the potential to promote regeneration of nervous tissue after cerebral cortex injury.

Experimental repair of phrenic nerve using a polyglycolic acid and collagen tube.

OBJECTIVE: The feasibility of a nerve guide tube for regeneration of the phrenic nerve with the aim of restoring diaphragmatic function was evaluated in a canine model. METHODS: The nerve tube, made of woven polyglycolic acid mesh, had a diameter of 3 mm and was filled with collagen sponge. This polyglycolic acid-collagen tube was implanted into a 10-mm gap created by transection of the right phrenic nerve in 9 beagle dogs. The tubes were implanted without a tissue covering in 5 of the 9 dogs (group I), and the tubes were covered with a pedicled pericardial fat pad in 4 dogs (group II). Chest x-ray films, muscle action potentials, and histologic samples were examined 4 to 12 months after implantation. RESULTS: All of the dogs survived without any complications. x-ray film examination showed that the right diaphragm was paralyzed and elevated in all dogs until 3 months after implantation. At 4 months, movement of the diaphragm in the implanted side was observed during spontaneous breathing in 1 dog of group I and in 3 dogs of group II. In the dogs showing diaphragm movement, muscle action potentials were evoked in the diaphragm muscle, indicating restoration of nerve function. Regeneration of the phrenic nerve structure was also examined on the reconstructed site using electron microscopy. CONCLUSION: The polyglycolic acid-collagen tube induced functional recovery of the injured phrenic nerve and was aided by coverage with a pedicled pericardial fat pad.

New canine spinal cord injury model free from laminectomy.

The present report details the successful development of a model for spinal cord injury (SCI). This model is simple, reproducible, and requires no laminectomy. Development of the model was carried out using fourteen dogs. A balloon catheter was inserted into the extradural space via the intervertebral foramen of each dog, then the balloon was inflated at the L1 level by injection of saline. Six dogs underwent compression with a balloon volume of 1.5 ml, three dogs with a volume of 1.0 ml, and the remaining five dogs were used as uninjured controls. We applied the Basso, Beattie, and Bresnahan (BBB) locomotor rating scale to the dogs. Compression of the spinal cord for 10 min at 1.5 ml produced severe paraplegia (BBB remained zero or one for 6 months following surgery), while compression for the same time interval at 1.0 ml produced moderate paraplegia. Electrophysiological tests showed no hindlimb movement upon stimulation cranial to the site of injury in the 1.5-ml group. The volume of abnormal-intensity lesions in the 1.0-ml group calculated using MR imaging showed no marked changes in either high- or low-intensity lesions after 3 months, whereas in the 1.5-ml group, the low-intensity lesions alone showed a marked increase. Pathological examination of the damaged spinal cord showed the formation of cavities surrounded by scar tissue containing high levels of collagen. These findings closely resembled those of clinical cases. It was concluded that 10 min of balloon compression with a volume of 1.5 ml caused irreversible paraplegia in dogs.

Experimental study on the regeneration of peripheral nerve gaps through a polyglycolic acid-collagen (PGA-collagen) tube.

We have developed a bioabsorbable polyglycolic acid (PGA) tube filled with collagen sponge (PGA-collagen tube) as a nerve connective guide, and compared its effectiveness with that of autograft in terms of nerve regeneration across a gap. The PGA-collagen tube was implanted into 24 beagle dogs across a 15-mm gap in the left peroneal nerve. The right peroneal nerve was reconstructed with the autograft harvested from the left side, as a control. After the surgery, the connective tissue extended from both cut ends in the PGA-collagen tube and connected again at the center. Pathologically, the collagen sponge in the tube provided adequate scaffolding for nerve tissue extension, and the nerve tissue reconnected within 3 weeks. Electrophysiologically, muscle-evoked potentials (MEPs) and compound nerve action potentials (CNAPs) were detected 18 days after the surgery. For up to 6 months postsurgery, CNAPs and somatosensory-evoked potentials (SEPs) on the PGA-collagen side had a shorter latency and larger peak voltage than those on the autograft side. The myelinated axons on the PGA side were larger in diameter than those on the autograft side. It is suggested that the PGA-collagen tube has the potential to be an effective alternative to conventional autografting for the repair of some peripheral nerve defects.

Repairing of rabbit skull defect by dehydrothermally crosslinked collagen sponges incorporating transforming growth factor beta1.

Collagen sponges of various biodegradabilities were prepared by dehydrothermal crosslinking at 140 degrees C for different time periods. When the collagen sponges were radioiodinated and implanted subcutaneously into the back of mice, the radioactivity remaining at the implanted site decreased with time; the longer the time of dehydrothermal crosslinking, the slower the radioactivity decrement. The radioactivity following the subcutaneous implantation of collagen sponges incorporating (125)I-labeled transforming growth factor (TGF)-beta1 also decreased with time. The time profile of both the radioactivity remainings was in good accordance to each other, irrespective of the crosslinking time. This indicates that the TGF-beta1 incorporated in the sponges was released as a result of sponge biodegradation. Potential of collagen sponges incorporating 0.1 micro g of TGF-beta1 in repairing the defect of rabbit skulls was evaluated in a stress-unloaded state. Bone repairing was induced by application of the collagen sponges incorporating 0.1 micro g of TGF-beta1 whereas that of free TGF-beta1 at the same dose and TGF-beta1-free, empty collagen sponges were ineffective. The bone defect was histologically closed by the bone tissue newly formed 6 weeks after application. Bone mineral density (BMD) analysis revealed that the collagen sponge incorporating TGF-beta1 enhanced the BMD value at the bone defect to a significantly great extent compared with other agents. A maximum enhancement of BMD was observed for the collagen sponge incorporating TGF-beta1 which was prepared by dehydrothermal crosslinking for 6 h. It was concluded that the TGF-beta1 incorporated in the collagen sponge was released in a biologically active form as a result of sponge biodegradation, resulting in enhanced bone repairing at the skull defect. It is possible that for too slowly degraded sponges, the remaining physically impairs the bone repairing at the skull defect. Induction of bone repairing would not be achieved through a rapid release of TGF-beta1 from too fast-degraded sponge.

Influence of dehydrothermal crosslinking on the growth of PC-12 cells cultured on laminin coated collagen.

Recently, we have demonstrated canine peroneal nerve regeneration with functional recovery across an 80 mm gap using a polyglycolic acid (PGA) -collagen tube filled with laminin coated collagen fibers. In that study, the laminin coating was applied before a dehydrothermal (DHT) treatment designed to extend preservation of laminin in situ. To address concerns that the biological activity of laminin might consequently be reduced, the present investigation examined the influences of DHT crosslinking on the activity of laminin in terms of neural cell growth in vitro. DHT crosslinking was performed on collagen (type I or IV) spread on glass in three groups: (1) before coating, (2) after coating, and (3) both before and after coating. PC-12 cells were disseminated in each of the three groups. All three groups were cultured, and the number of cells were compared statistically. Cell growth achieved through application of laminin coating after DHT crosslinking was statistically greater than that achieved when laminin coating was performed before crosslinking. A reduction in laminin activity induced by DHT crosslinking was demonstrated. The optimal timing for the crosslinking of biornaterials treated with trophic factors such as-laminin should be examined in terms of the effects of crosslinking on the activity of the trophic factors.