Microsurgical Suture Research Articles

Comparison of vasovasostomy with conventional microsurgical suture and fibrin adhesive in rats

Microsurgical procedures are currently the gold standard for vasovasostomy with excellent results, but it takes an increased operative time demanding special training and experience in microsurgery. The objective of this study is to reach the same results with reduced operative time. Male adults Wistar rats were divided into 3 groups: I) 20 rats in control group, II) 20 with conventional one-layer microsuture and III) 20 with fibrin glue. After four weeks each rat was left for two weeks with two female rats. The fertility rates were 80% in group I, 70% in group II and 65% in group III (p > 0.05). In group II granuloma was found in 75% of the rats, while in group III in 85% (p < 0.05). Anastomosis was considered with patency in 75% and 80% of the rats in groups II and III (p > 0.05). Overall operative time was 41.7 +/- 2.49 and 28.55 +/- 1.14 minutes in groups II and III (p < 0.05) and the time to anastomosis of 24.6 +/- 1.8 and 9.35 +/- 0.78 minutes (p < 0.05), respectively. We can conclude that vasovasostomy with fibrin adhesive has the same results of the conventional microsurgery technique but with a reduced operative time and a simplified procedure.

Microvascular anastomosis using a photochemical tissue bonding technique

Photochemical tissue bonding (PTB) combines photoactive dyes with visible light to create fluid-tight seals between tissue surfaces without causing collateral thermal damage. The potential of PTB to improve outcomes over standard of care microsurgical reanastomoses of blood vessels in ex vivo and in vivo models was evaluated. The mechanical strength and integrity of PTB and standard microsurgical suture repairs in ex vivo porcine brachial arteries (n = 10) were compared using hydrostatic testing of leak point pressure (LPP). Femoral artery repair in vivo was measured in Sprague-Dawley rats using either standard microvascular sutures (n = 20) or PTB (n = 20). Patency was evaluated at 6 hours (n = 10) and 8 weeks post-repair (n = 10) for each group. PTB produced significantly higher LPPs (1,100+/- 150 mmHg) than suture repair (350+/-40 mmHg, P<0.001) in an ex vivo study. In an in vivo study all femoral arteries in both suture and PTB repair groups were patent at 6 hours post-repair. At 8 weeks post-repair the patency rate was 80% for both groups. No evidence of aneurysm formation was seen in either group and bleeding was absent from the repair site in the PTB-treated vessels, in contrast to the suture repair group. PTB is a feasible microvascular repair technique that results in an immediate, mechanically robust bond with short- and long-term patency rates equal to those for standard suture repair.

Poster 236: Chopstick Rest Technique: A New Ultimate Technique of Microvascular Suturing

Statement of the ProblemNowadays, microvascular suturing technique is very important for head and neck reconstruction. However, microsurgical procedure is sometimes a time consuming act. The main reasons that make microsurgery a time consuming act is as follows:1)The act of making a loop around the forceps in narrow and deep area is sometimes difficult and time consuming.2)The loose end of the suture may be difficult to pick up again, once dropped into the operative field because it gets stuck to the surrounding tissues. In the process of retrieving the suture, the surrounding tissues can be picked up together with the suture.3)When the posterior wall technique is used, the loose end of the suture may get stuck to the backside of the vessel and may be difficult to grab.Materials and MethodsTo solve these problems, we created a new technique named the “Chopstick Rest Technique” as the ultimate technique of microsurgical suturing.The advantages are as follows1)No need to make a loop around the forceps.2)No need to pick up the short end of the thread from the operative field.3)The movement is only short, linear back and forth movements of each hand.Method of Data Analysisno data analysis, only video presentationResultsThis technique is undoubtedly simpler than the usual methods, so it may contribute time saving. Moreover this technique is very good for untied suturing situation.ConclusionThere is a possibility that this technique will become the next generations’ standard microsurgical suturing technique because of its reasonable theory and simplicity. Statement of the ProblemNowadays, microvascular suturing technique is very important for head and neck reconstruction. However, microsurgical procedure is sometimes a time consuming act. The main reasons that make microsurgery a time consuming act is as follows:1)The act of making a loop around the forceps in narrow and deep area is sometimes difficult and time consuming.2)The loose end of the suture may be difficult to pick up again, once dropped into the operative field because it gets stuck to the surrounding tissues. In the process of retrieving the suture, the surrounding tissues can be picked up together with the suture.3)When the posterior wall technique is used, the loose end of the suture may get stuck to the backside of the vessel and may be difficult to grab. Nowadays, microvascular suturing technique is very important for head and neck reconstruction. However, microsurgical procedure is sometimes a time consuming act. The main reasons that make microsurgery a time consuming act is as follows:1)The act of making a loop around the forceps in narrow and deep area is sometimes difficult and time consuming.2)The loose end of the suture may be difficult to pick up again, once dropped into the operative field because it gets stuck to the surrounding tissues. In the process of retrieving the suture, the surrounding tissues can be picked up together with the suture.3)When the posterior wall technique is used, the loose end of the suture may get stuck to the backside of the vessel and may be difficult to grab. Materials and MethodsTo solve these problems, we created a new technique named the “Chopstick Rest Technique” as the ultimate technique of microsurgical suturing. To solve these problems, we created a new technique named the “Chopstick Rest Technique” as the ultimate technique of microsurgical suturing. The advantages are as follows1)No need to make a loop around the forceps.2)No need to pick up the short end of the thread from the operative field.3)The movement is only short, linear back and forth movements of each hand. 1)No need to make a loop around the forceps.2)No need to pick up the short end of the thread from the operative field.3)The movement is only short, linear back and forth movements of each hand. Method of Data Analysisno data analysis, only video presentation no data analysis, only video presentation ResultsThis technique is undoubtedly simpler than the usual methods, so it may contribute time saving. Moreover this technique is very good for untied suturing situation. This technique is undoubtedly simpler than the usual methods, so it may contribute time saving. Moreover this technique is very good for untied suturing situation. ConclusionThere is a possibility that this technique will become the next generations’ standard microsurgical suturing technique because of its reasonable theory and simplicity. There is a possibility that this technique will become the next generations’ standard microsurgical suturing technique because of its reasonable theory and simplicity.

Innovative Single-Armed Suture Technique for Microsurgical Vasoepididymostomy

Vasoepididymostomy outcomes are heavily dependent on the surgeon's microsurgical experience and skill. To avoid back-walling the tubular lumen, the needles are generally placed inside-out through the vasal lumen using double-armed microsutures. These double-armed sutures for infertility microsurgery are very expensive and may be difficult to obtain. We describe a randomized trial that used a novel single-armed suture placement pattern for vasoepididymostomy. Male adult Wistar rats underwent vasectomy. Two weeks later, vasoepididymostomies were performed using either a single-armed longitudinal intussusception vasoepididymostomy (n = 6) or a standard double-armed longitudinal intussusception vasoepididymostomy (n = 6) technique. After 9 weeks, patency was assessed functionally by evaluating for motile sperm distal to the anastomosis. If no motile sperm were visible, the mechanical patency of the anastomoses was tested by the ability of methylene blue to pass through the surgical anastomosis. The patency rate for the double-armed vasoepididymostomy group was 100% (6 of 6) compared with 83.3% (5 of 6) for the single-armed vasoepididymostomy group. This difference was not significant (P = 0.50). Sperm granulomas were found in three (50%) of six anastomoses in the double-armed group and five (83%) of six anastomoses in the single-armed vasoepididymostomy group (P = 0.27). The mean operative times for the double and single-armed longitudinal intussusception vasoepididymostomy techniques were similar (35 minutes versus 43 minutes; P = 0.39). The results of our study have shown that the single-armed suture technique to perform vasoepididymostomy is almost as effective as the double-armed technique. Although we still prefer to use double-armed sutures, we believe that this is a practical and effective alternative when specialized double-armed microsurgical sutures are not available.

Microsurgical nonmicrovascular flaps in forearm and hand reconstruction

Relatively new method in flap's surgery, perforator flaps tends to monopolize nowadays the surgeon's interest. The question is: could these flaps be used not only as free flaps, as were mainly used until now, but also as local or regional flaps? On the basis of our experience with 115 operated cases, we will try to demonstrate that a lot of simple or composite defects in the forearm and hand could be covered, in selected cases, by using local or regional perforator flaps. This may have as result, in the future, a dramatic decrease in the indication for free flap transfers. Because these flaps need a microsurgical dissection, but do not need microvascular sutures, they could be defined as "microsurgical nonmicrovascular flaps." The main advantages of these flaps could be summarized as: no microsurgical sutures, no main vascular pedicles sacrifice, same surgical field, shorter hospitalization time.

P67 Microsurgical suture of the periosteal flap in autologous chondrocyte implantation: two to eight years follow-up study

P67 Microsurgical suture of the periosteal flap in autologous chondrocyte implantation: two to eight years follow-up study

Facial-Hypoglossal Nerve Anastomosis Using Laser Nerve Welding

The aim of this study is to compare laser nerve welding to microsurgical suturing of hypoglossal-facial nerve anastomosis (HFA), and a result of immediate to delayed repair, and to evaluate the effect of laser nerve welding on HFA for reanimation of facial palsy. The first group of five rats underwent immediate HFA by microsurgical suturing and the second group of five rats by CO2 laser welding. The third group of five rats underwent delayed HFA by microsurgical suturing, and the fourth group of five rats by laser nerve welding. The fifth group of five rats served as controls, with intact hypoglossal and facial nerve. In all rats of the four different treatment groups, cholera toxin B subunit (CTb) was injected in the epineurium distal to the anastomosis site on the postoperative 6th week and in the normal hypoglossal nerve in the five rats of the control group. Neurons labeled CTb of hypoglossal nuclei were positive immunohistochemically, and the numbers were counted. In the immediate HFA groups, CTb-positive neurons were 751 +/- 247 in the laser welding group (n = 5) and 888 +/- 60 in the microsurgical suturing group (n = 5). There was no significant difference (P = 0.117). In the delayed HFA groups, CTb-positive neurons were 749 +/- 54 in the laser welding group (n = 5) and 590 +/- 169 in the microsurgical suturing group (n = 5). The difference was not significant (P = 0.116). There was no significant difference between immediate and delayed anastomosis in the laser welding group (P = 0.600), but there was significance between immediate and delayed anastomosis in the microsurgical suturing group (P = 0.009). Injected CTb in intact hypoglossal neurons (n = 5) were labeled 1,003 +/- 52. No dehiscence in the laser welding site of nerve anastomosis was seen at the time of re-exploration for injection of CTb in all 10 rats. This study shows that the regeneration of anastomosed hypoglossal-facial nerve was affected similarly by laser welding and microsurgical suturing, and more effective, especially in delayed repair.

The Role of Defensin NP-1 in Restoring the Functions of an Injured Nerve Trunk

This report presents results from studies on the actions of neutrophil defensin NP-1 on the initial stage of regeneration of the lesioned sciatic nerve in rats. The effects of defensin on the growth rate and functional characteristics of regenerating nerve fibers were assessed by recording total action potentials 21 days after transection and microsurgical suturing of the nerve. These experiments showed that defensin increased the rate of growth of regenerating nerve fibers by 30%: the distance over which nerve spike conductivity was restored in the lesioned nerve increased from 7.2 +/- 1.2 (control) to 10.5 +/- 0.8 mm (experiment) from the suturing site (p < 0.05). In addition, an increase in the excitation conduction rate along the regenerating nerve fibers by 20% compared with control was observed. Overall, the results provide evidence for the positive effects of defensin on restoration of the functions of the lesioned nerve trunk.

Establishing Normal Values of the Proximal Median Motor Nerve−A Study of the Pronator Teres and Flexor Carpi Radialis in Healthy Volunteers

The importance of normative peripheral nerve data is increasing due to advances in medical implantation, microsurgical suturing, and tubulization repair techniques. Because the median nerve is often affected, its normal values must be reliable. Although the distal portion of the median nerve has been well studied using electrodiagnostic methods, the proximal forearm segment has not. This study establishes a normative database for median nerve conduction to the pronator teres (PT) and to the flexor carpi radialis (FCR). Two hundred-eight asymptomatic subjects were studied using proximal median motor stimulation at 10 cm. Latencies, amplitudes, areas, and durations were recorded. To the pronator teres: The upper limit for normal (ULN) motor latency was 3.5 ms (2.9 +/- 0.3 ms). The side-to-side latency difference was </= 0.5 ms. Overall, the lower limit of normal (LLN) amplitude was 2.2 mV. However, this decreased to 1.5 mV in the over-50 age group. To the flexor carpi radialis: The ULN motor latency was 3.6 ms (2.8 +/- 0.4 ms). The side-to-side latency difference was </= 0.7 ms. Overall, the LLN amplitude was 2.3 mV. However, this decreased to 1.7 mV in the over-50 group. This study produced a large database of normal results for the median motor nerve conduction to the pronator teres and to the flexor carpi radialis. The 10-cm techniques are easily reproducible and helpful when evaluating this portion of the median nerve.

Establishing Normal Nerve Conduction Values− Lumbrical and Interosseous Responses

The importance of normative peripheral nerve data is increasing due to the advances in medical implantation, microsurgical suturing, and tubulization repair techniques. Because the median and ulnar nerves are often affected, their normal values must be reliable. The objective of this study was to create a larger database of normative values for the first and second lumbrical responses. The differences between the second lumbrical response and the interosseous response were also studied. The available literature is lacking in sample size and rigor, preventing reliable interpretations of normal values. One hundred ninety-six asymptomatic subjects without risk factors for neuropathy were recruited and tested. Stimulations were performed with recording at the first lumbrical, second lumbrical, and interosseous muscles. Mean latency to the first lumbrical was 3.6 +/- 0.4 ms. Mean amplitude was 2.5 +/- 2.0 mV. The mean difference between latencies to the first lumbrical and second lumbrical was 0.1 +/- 0.3 ms, with the second lumbrical usually being the larger value. The mean difference between latencies to the abductor pollicic brevis (APB) and the first lumbrical was 0.2 +/- 0.4 ms, with the APB latency usually being the larger value. Mean latency to the second lumbrical was 3.7 +/- 0.4 ms and to the interosseous was 3.1 +/- 0.3 ms. Mean amplitude to the second lumbrical was 3.0 +/- 2.0 mV and to the interosseous was 6.9 +/- 2.3 mV. The mean difference between latencies to the second lumbrical and interosseous was 0.4 +/- 0.4 ms, with the second lumbrical usually being the larger value. The upper limit of normal increase of latency of the second lumbrical over the interosseous was 1.2 ms. The upper limit of normal increase of latency in subjects for which the interosseous latency exceeded the second lumbrical was 0.2 ms. This study provides a large normative database for nerve conduction studies to the first and second lumbricals, as well as to the second interosseous muscle.

Learning microsurgical suturing and knotting techniques: comparative data

Correctly performed surgical sutures are the basis of surgical safety. This retrospective survey was conducted among participants (n = 263) taking graduate and postgraduate courses between 2000-2004. Placement of sutures, time to perform knotting, safety of knots, and quality of knot stability were tested. None of the students had been previously instructed in microsurgical techniques. At the beginning of the training program, 90-95% of participants damaged the suturing thread at several places. By the end of the course, knotting times significantly decreased in both groups. Graduates decreased their time from 6.8 +/- 2.34 min to 3.28 +/- 0.71 min (mean +/- standard error of the mean), and postgraduates decreased their time from 5.02 +/- 3.25 min to 1.54 +/- 0.54 min (mean +/- standard error of the mean). In our opinion, "mass training" to teach the basics of microsurgery is not a good approach. Instead, individual training should be provided, as tutors offer invaluable advice, and adjust almost each stitch and knot during teaching sessions.

Laser Welding of Rat's Facial Nerve

The aim of this study is to compare regeneration of the severed nerves that were repaired by laser welding with those repaired by microsurgical suturing and evaluate the value in use of laser nerve welding in the head and neck area. In 12 rats the buccal branches of the facial nerves on the both sides were transected, and CO2 laser welding of the epineurium was performed on the right side and microsurgical suture technique was applied on the left side. In six rats Cholera Toxin B Subunit (CTb) was injected in the epineurium distal to the nerve anastomosis site at postoperative week 4. Another six rats were treated exactly in the same way in postoperative week 8. Six normal rats were used as controls. Intact facial nerve was observed after injection of CTb as well. Neurons of facial nuclei labeled positively by CTb were detected immunohistochemically, and the numbers were counted. CTb-positive neurons in the control group were 1311 +/- 258 (n = 6). CTb-positive neurons in the group (n = 6) with laser nerve welding were 1174 +/- 122 in postoperative week 4 and 1562 +/- 565 in postoperative week 8. CTb-positive neurons in the group (n = 6) with microsurgical suture were 1066 +/- 89 in postoperative week 4 and 1443 +/- 531 in postoperative week 8. CTb-positive neurons were seen significantly more in the group with laser welding than in the group with microsurgical suture in postoperative week (P = 0.028), but there was not much difference in postoperative week 8 (P = 0.463). None of 12 rats showed dehiscence at the nerve anastomosis done by laser welding. This study shows that nerve regeneration is more apparent in the nerve repaired by laser welding than in that repaired by microsurgical suture.

Microsurgical skills training: A new concept for simulation of vessel-wall suturing

Initiation of training in basic microsurgical suturing technique usually involves placing sutures on incisions made on latex sheets, and then progressing to a live anastomosis in a rat model. A straight incision resembles a skin incision and does not mechanically simulate vessel wall suturing, and various modifications and innovative prosthetic models continue to be developed to bring the simulation closer to a live anastomosis. We developed two models which closely simulate vessel wall suturing and require the application of similar skills by the trainee. In the first model (the "I" model), the straight 1-cm incision is converted to an I-shaped incision which increases the instability of the edge to be sutured, depending on the length of the horizontal incision, putting greater demand on dexterity in suture placement similar to a vessel. The length (1 cm) of the edge does not constrain the spacing of the sutures and can be used for the beginner. The second model (the "double triangle" model) creates a narrow and unstable edge for placing sutures, and puts greater demand on bimanual coordination and instrument control for training in accuracy of suture placement as well as spacing between sutures. Both these models are cost-effective and simple to construct.

ROBOTIC MICROSURGICAL VASOVASOSTOMY AND VASOEPIDIDYMOSTOMY: A PROSPECTIVE RANDOMIZED STUDY IN A RAT MODEL

Microsurgical vasovasostomy and vasoepididymostomy remain technically challenging procedures. Refinements in technique have continually improved patency and pregnancy rates for the 2 procedures in experienced hands. Advances in surgical robotics produced the Da Vinci robot (Intuitive Surgical, Inc., Sunnyvale, California) with motion reduction and no tremor, features that may improve outcomes in microsurgery. We report a randomized prospective study of vasoepididymostomy and vasovasostomy using the Da Vinci robot in rats. A total of 24 adult male Wistar rats underwent vasectomy through a midline abdominal incision. Two weeks later the animals were randomized to microsurgical multilayer vasovasostomy, longitudinal vasoepididymostomy or robotic vasovasostomy and vasoepididymostomy groups. Outcomes measured included surgical time, complications, patency and sperm granuloma formation at 9 weeks. Animals were sacrificed 9 weeks after microsurgery. There were no significant differences in complications among the groups. Robotic vasovasostomy was significantly faster than the conventional microsurgical technique (68.5 vs 102.5 minutes, p = 0.002). The robotic and microsurgical vasoepididymostomy groups did not differ significantly in time. Patency rates were 100% for the robotic vasovasostomy and vasoepididymostomy groups, and 90% in the microsurgical vasovasostomy and vasoepididymostomy groups. These differences were not significant. Sperm granulomas were found in 70% of microsurgical vasovasostomy anastomoses and 27% of robotic vasovasostomy anastomoses (p = 0.001). No significant difference in the sperm granuloma rate was found between the robotic or microsurgical vasoepididymostomy groups (42% and 50%, respectively, p = 0.37). To our knowledge we report the first randomized prospective study using the Da Vinci robot for microsurgery. We believe that the improved stability and motion reduction during microsurgical suturing with the robot helped achieve excellent patency rates for vasovasostomy and vasoepididymostomy. The robot may also allow experienced microsurgeons to perform microsurgical procedures in patients at remote locations where no experienced microsurgeons are available.

Application of a Surgical Robot to Open Microsurgery: The Equipment

Background: Computer-assisted robot-enhanced surgery can enhance minimally invasive surgery by providing a wrist at the end of the instruments and by scaling motion and filtering tremor. Motion scaling and tremor filtration are most enabling at high magnification. Goal: To explore the possibility of using a surgical robot designed for minimally invasive surgery during open microsurgical procedures. Materials and Methods: Using the Zeus MicroWrist™ Robotic Surgical System in conjunction with the triple-alpha port, we performed suture tasks on a glove box with microsurgical suture (8-0 to 10-0) in three different configurations. First, we used a standard 10- mm laparoscope, camera, and the Zeus monitor. Next, we used an operating microscope for visualization with the surgeon at the operative table while controlling the instruments. Third, we allowed the surgeon to sit at the standard Zeus console and transmitted the image from the microscope to the monitor at the Zeus console. Results: In all three configurations, we were able to manipulate small suture effectively. Using the standard laparoscope, we measured a maximum working magnification of 27 times. At the maximum magnification, we had some difficulty resolving 10-0 suture. Using the operative microscope, we found that the surgeon was crowded by equipment. However, the maximum working magnification was 50 times, the resolution of the fine suture was excellent, and the surgeon had better depth perception. Connecting the operating microscope to the video monitor combined the best features of both systems. Conclusion: We effectively used the Zeus system in manipulating microsurgical suture with both a standard laparoscope and a surgical microscope. The microscope provides better visualization. We plan to explore this application of the surgical robot further by working in a microsurgical animal model.

Validation of novel and objective measures of microsurgical skill: Hand‐motion analysis and stereoscopic visual acuity

Our purposes were: 1) to establish the predictive validity of stereoscopic visual acuity and microsurgical performance, and 2) to establish the construct and concurrent validity of hand-motion analysis as an objective and sensitive measure of microsurgical performance. Using a surgical microscope, 50 surgical residents completed a standardized microsurgical suturing task at baseline and following microsurgical training. Microsurgical performance was evaluated by blinded, expert microsurgeons using global rating scales. Measures of stereoscopic visual acuity and hand-motion analysis were correlated with expert global rating scores. Global rating scores correlated significantly with number of hand movements (r = -0.47, P = 0.001) and hand-travel distance (r = -0.37, P = 0.008). Economy of hand-motion improved significantly following microsurgical training (number of hand movements, P = 0.046; hand-travel distance, P = 0.04). Measures of stereoscopic visual acuity did not correlate significantly with global rating scores. Hand-motion analysis appears to be an objective and sensitive instrument for assessing microsurgical performance, with evidence of both concurrent and construct validity. The predictive validity of stereoscopic visual acuity and microsurgical performance remains unclear.

Carbon dioxide laser-assisted nerve repair: effect of solder and suture material on nerve regeneration in rat sciatic nerve.

In order to further improve and explore the role of lasers for nerve reconstruction, this study was designed to investigate regeneration of sharply transected peripheral nerves repaired with a CO(2) milliwatt laser in combination with three different suture materials and a bovine albumin protein solder as an adjunct to the welding process. Unilateral sciatic nerve repair was performed in 44 rats. In the laser group, nerves were gently apposed, and two stay sutures (10-0 nylon, 10-0 polyglycolic acid, or 25 microm stainless steel) were placed epi/perineurially. Thereafter, the repair site was fused at 100 mW with pulses of 1.0 s. In the subgroup of laser-assisted nerve repair (LANR), albumen was used as a soldering agent to further reinforce the repair site. The control group consisted of nerves repaired by conventional microsurgical suture repair (CMSR), using 4-6 10-0 nylon sutures. Evaluation was performed at 1 and 6 weeks after surgery, and included qualitative and semiquantitative light microscopy. LANR performed with a protein solder results in a good early peripheral nerve regeneration, with an optimal alignment of nerve fibers and minimal connective tissue proliferation at the repair site. All three suture materials produced a foreign body reaction; the least severe was with polyglycolic acid sutures. CMSR resulted in more pronounced foreign-body granulomas at the repair site, with more connective-tissue proliferation and axonal misalignment. Furthermore, axonal regeneration in the distal nerve segment was better in the laser groups. Based on these results, CO(2) laser-assisted nerve repair with soldering in combination with absorbable sutures has the potential of allowing healing to occur with the least foreign-body reaction at the repair site. Further experiments using this combination are in progress.

Impact of poor microsurgical suture technique on tissue perfusion in a rat model.

This study was designed to evaluate the effect of poor suture technique in microsurgical small-vessel anastomosis on tissue microcirculation. Eighteen male Sprague-Dawley rats were divided into three groups of six animals each: sham control group, regular suture group (control), and inverting suture group. In the regular suture group, a standard single-stitch suture technique was used for microsurgical reanastomosis of the transected common iliac artery. In the inverting suture group, a suture technique was applied inverting the vessel wall, thus simulating poor suture technique. After 24 h, intravital microcirculatory measurements were obtained in the cremaster muscle flap. The inverting suture caused a significant drop in capillary perfusion from 6.40 (sham control) and 5.65 (regular suture) to 1.81 capillaries per visual field (P < 0.005). A poor microsurgical anastomosis may result in a significant reduction of peripheral tissue perfusion, although blood flow through the main feeding vessel is maintained.

Training for advanced laparoscopic surgery.

To evaluate the efficiency of training for advanced minimally-invasive surgery in rats. Teaching hospital, Germany. 10 surgical residents with few laparoscopic training skills had two days laparoscopic microsurgical training using rats. Increasingly difficult procedures started using a rubber model, followed by 'open' and 'closed' rat models simulating laparoscopic conditions. The surgical skills of all participants were assessed before and after the laparoscopic training course by applying 5 defined tasks in a simulation trainer. As a control group, 8 surgical residents with the same amount of minimal-invasive training were tested after a 2-day interval. All participants of the laparoscopic training programme significantly improved their surgical skills for all 5 tasks (p < 0.05). In the control group only one of the 5 tasks was significantly improved after repetition. Participants of the complete training programme consistently improved their surgical skills significantly compared with the controls before and after repetition (p < 0.05). Surgical training in minimal-invasive techniques in the rat model is effective and reproducible especially to improve laparoscopic skills such as bimanual tissue handling, knot tying and microsurgical suturing.

Microsurgical instrumentation and suture material.

Microsurgery requires specialized instruments and very fine suture material. The authors describe microsurgical instruments and suturing materials available for small animal microsurgery.