Peter Mailaender

Persistence of pedicle blood flow up to 10 years after free musculocutaneous tissue transfer

&NA; The hypothesis of whether or not flap perfusion remains persistent through its vascular pedicle up to 10 years after free tissue transfer was tested. Since 1982, more than 1,000 free tissue transfers have been performed at this institution. Of these, 40 patients were selected with comparable posttraumatic soft‐tissue defects of the lower leg and surgical repair by a latissimus dorsi myocutaneous free flap. All patients had a postoperative course free of complications. Measurements of flap perfusion were started in groups 1 through 4 (each 10 patients) 3 to 5 weeks, 5 to 7 months, 4 to 6 years, and 8 to 10 years after free tissue transfer, respectively. Quantitative measurements of local flap perfusion were performed by means of the hydrogen clearance technique (Ameda, Switzerland) at definite sites intracutaneously and subcutaneously within the flaps skin paddle as well as in the adjacent intracutaneous and subcutaneous skin of the surrounding soft tissue. Simultaneously, the vascular pedicle of the flap was visualized by a duplex scanner (Toshiba, Japan). In each group nine measurements were performed before (phase A), during (phase B), and after closing the pedicle (phase C) by manual compression. Each measurement took about 10 minutes. Statistical evaluation of the obtained values was achieved by the Mann‐Whitney U test and the Wilcoxon signed rank test. Local flap perfusion showed no statistical differences for phase A and C in all four groups of patients. In phase B, however, a statistically highly significant (p < 0.01) absence of local flap perfusion was registered in all four groups at the site of the flaps skin paddle. No statistically significant alterations of intracutaneous and subcutaneous blood flow was found in the surrounding soft tissue. In our clinical‐experimental setting, flap perfusion persisted by means of its vascular pedicle even 10 years after free tissue transfer. Our findings support the importance of an intact vascular pedicle for permanent flap survival after free tissue transfer.

Prospective clinical study on digital nerve repair with collagen nerve conduits and review of literature.

Little data are available concerning conduit repair of digital nerve lesions. We are presenting a prospective two-center cohort study on digital nerve reconstruction with collagen nerve conduits. The data are put into the context of a comprehensive review of existing literature. Over a period of 3 years, all consecutive digital nerve lesions that could not be repaired by tensionless coaptation with a gap length of less than 26 mm were reconstructed with nerve conduits made from bovine collagen I. Sensibility was assessed 1 week, 3, 6, and 12 months postoperatively by static and moving 2-point-discrimination (2PD) and monofilament testing. Forty-nine digital nerve lesions in 40 patients met the inclusion criteria. The mean nerve gap was 12.3 ± 2.3 mm (span 5-25 mm). Forty nerve reconstructions could be included in the 12-month follow-up. Three cases, assessed 12 months postoperatively, showed excellent sensibility (static 2PD <6 mm). Seventeen achieved good (2PD 6-10 mm), 5 fair (2PD 11-15 mm), 6 poor (2PD >15 mm, but protective sensibility), and 9 achieved no sensibility. Monofilament test results were significantly better if gap length was shorter than 12 mm. Our results confirm tubulization as one possible technique in nerve reconstruction for gap lengths of 5 to 25 mm.

Postoperative blood flow monitoring after free-tissue transfer by means of the hydrogen clearance technique.

&NA; The hydrogen clearance technique was introduced for monitoring postoperative blood flow after free‐tissue transfer in this prospective clinical study. This technique allows unlimited repeatable quantitative measurements of tissue blood flow in milliliters per minute per 100 gm of tissue at any site including buried flaps. In this study a real‐time blood flow measuring system (Ameflow, Ameda, Switzerland) was employed. Two thousand eight hundred and twenty‐three blood flow measurements were carried out on 72 free‐tissue transfers, which were performed on 71 patients. Nine of these 72 flaps showed vascular complications (12.5 percent), including arterial thrombosis in 6.9 percent (n = 5), hematoma in 4.2 percent (n = 3), and venous thrombosis in 1.4 percent (n = 1). Complications as well as uneventful postoperative cases were monitored correctly by the hydrogen clearance technique in all cases, reaching sensitivity and specificity values of 1.0 for this technique in our study. Furthermore, all complications could be detected earlier by the hydrogen clearance technique than by clinical monitoring alone, which allowed flap salvation in 7 of 9 cases and a resulting permanent failure rate of free‐tissue transfer of 2.8 percent (n = 2). From our data we conclude that the hydrogen clearance technique is a promising tool for postoperative blood flow monitoring after free‐tissue transfer. For experimental pathophysiologic and pharmacologic studies of tissue blood flow in flaps, further evaluation of our measuring device including comparative studies with other established techniques is highly recommended.

Management of difficult intra-articular fractures or fracture dislocations of the proximal interphalangeal joint

Intra-articular fractures or fracture dislocations of the proximal interphalangeal joint are difficult clinically because the bone and soft tissue structures are small and intricate. Suboptimal treatment of intra-articular fractures typically leads to functional impairment of the hand. This article reviews the current methods of treatment, together with the senior author’s experience in treating difficult proximal interphalangeal joint fractures and dislocations. Besides conservative treatments, surgical treatments include open or closed reduction with traditional Osteosynthesis, such as K-wires, screws or plates. Among recent developments are the percutaneous application of thin cannulated compression screws and novel dynamic external fixators. After a preferred minimally invasive treatment with stable reconstruction of the articular surface, sufficient aftercare is necessary to improve surgical outcomes.

Local blood flow monitoring by means of the hydrogen clearance technique

The hydrogen clearance technique (HCT) allows quantitative measurements of local blood flow (LBF) in ml/min/lOO g tissue. Although this technique has been commonly employed in different fields of medicine, especially in neurology, the HCT has seldom been used in plastic surgery. We report a case of a 46-year-old male who was admitted to our hospital with claudication of the ulnar side of the right hand. Symptoms started 6 months earlier when the patient had suffered blunt trauma to the ulnar side of the right wrist. Preoperative angiography demonstrated occlusion of the ulnar artery with insufficient blood supply for the 4th and 5th digits. Skin LBF was 12.6-14.0 ml/min/lOO g and 13.5-16.8 ml/min/ 100 g, respectively, measured by the HCT (monitoring device by Ameda@/Switzerland). Skin LBF of the 1st and 2nd digit showed significantly higher values: 52.6-54.5 ml/min/lOO g* and 53.8-56.3 ml/min/lOO g*, respectively. Following revascularization by an autologous vein-graft, postoperative angiography revealed a patent ulnar artery with adequate perfusion of digits 4 and 5. Skin LBF, measured on the 6th postoperative day, was significantly altered: 47.6-49.5 ml/min/lOO g* and 50.2-53.7 ml/min/lOO g*, respectively. Claudication had disappeared promptly. We believe that the HCT is a valuable method for monitoring postoperative blood flow following digital revascularization. *: P s 0.01

Removal of collagen nerve conduits (NeuraGen) after unsuccessful implantation: focus on histological findings.

Nerve conduits are nonneural, hollow tubular structures designed to bridge the gap of a sectioned nerve, to protect the nerve from scar formation, and to guide the regenerating fibers into the distal nerve stump. In the 8-year experience of our department, four patients aged 14 to 50 years had an unsuccessful implantation of a nerve conduit (NeuraGen, Integra, Plainsboro, NJ). In these four patients, the collagen tubes were replaced by an autogenous nerve graft. The histological specimens showed characteristic histological findings of a scar neuroma without any signs of foreign body reaction in three cases and with minimal foreign body reaction in one case. The collagen nerve tube was completely resorbed in all cases after a time period of 6 to 17 months and could not be detected marco- or microscopically.To our knowledge, this is the first report in the English and German literature describing the histological characteristics of explanted collagen nerve tubes in humans.

Technetium—99M human immunoglobulin (HIG): A new substance for scintigraphic detection of bone and joint infections

Technetium (99m‐Tc)‐labelled, polyclonal human immunoglobulin (HIG) has been described as a new agent to detect local infection and inflammation. In this study, we tested 99m‐Tc HIG in 55 patients with suspected chronic (n = 42) and acute (n = 13) skeletal infection. Diagnosis was proven operatively (n = 44) and clinically (n = 11), including microbiological culture tests (n = 46). A gamma camera scan was performed 4 and 24 hours after i.v. injection of 500 MBq 99m‐Tc‐HIG. 99m‐Tc‐HIG scanning achieved a sensitivity of 91% and a specificity of 93%. We found one false negative and five false positive scintigraphic results in 55 patients. No clinical or biochemical side effects were encountered after 99m‐Tc‐HIG injection. We recommend this technique especially for localisation of low‐grade, chronic osteomyelitis. The mechanisms and kinetics of 99m‐Tc‐HIG, however, are worth investigating more extensively.

The Use of Bone Graft Substitute in Hand Surgery: A Prospective Observational Study

AbstractBone defects are a very common problem in hand surgery, occurring in bone tumor surgery, in complicated fractures, and in wrist surgery. Bone substitutes may be used instead of autologous bone graft to avoid donor site morbidity. In this article, we will review our experience with the use of Cerament bone void filler (Bonesupport, Lund, Sweden) in elective and trauma hand surgery. A prospective clinical study was conducted with 16 patients treated with this bone graft substitute in our department over a period of 3.5 years. Twelve patients (2 female, 10 male; with an average age of 42.42 years) with monostoic enchondroma of the phalanges were treated and 4 patients (1 female, 3 male; with an average age of 55.25 years) with complicated metacarpal fractures with bone defect. Data such as postoperative course with rating of pain, postoperative complications, functional outcome assessment at 1, 2, 3, 6 months, time to complete remodeling were registered. Postoperative redness and swelling after bone graft substitute use was noticed in 7 patients with enchondroma surgery due to the thin soft-tissue envelope of the fingers. Excellent total active motion of the involved digit was noticed in 10 of 12 enchondroma patients and in all 4 fracture patients at 2-month follow-up. In summary, satisfying results are described, making the use of injectable bone graft substitute in the surgical treatment of enchondromas, as well as in trauma hand surgery a good choice.

Significant [C3a] Increase in Free Flaps After Prolonged Ischemia

BACKGROUND Free tissue transfer (FTT) represents a clinical model to measure ischemia-reperfusion injury (IRI). This study was conducted to detect substances relevant for IRI after FTT. METHODS Eighteen patients underwent lower leg reconstruction with free myocutaneous latissimus dorsi muscles and were monitored clinically and by microdialysis technique. Patients were retrospectively classified as group A (n = 12) (no prolonged IRI) or group B (n = 6) (prolonged IRI). One catheter was placed into the flap and one into the reference tissue. Samples were collected during ischemia and in 90 min steps after reperfusion. Biochemical substances (glucose, pyruvate, lactate, and glycerol) and immunological substances (interleukin 8 [IL-8], complement 3a [C3a], and regulated on activation normal T cell expressed and secreted [RANTES]) were then analyzed. RESULTS All free myocutaneous latissimus dorsi flaps healed primarily. Minor complications included revisions of the microvascular anastomoses due to hematoma or thrombus formation and increased total flap ischemia time in group B significantly when compared to group A (P < 0.001). No significant differences of biochemical substance concentrations were detected during reperfusion in target and control tissue of both groups. IL-8 and C3a were at detectable levels, whereas the results for RANTES were inconsistent. Either for group A and group B, we found higher concentrations of C3a in target tissue compared with control tissue. Furthermore, during the first 90 min of reperfusion, we found a highly significant increase of C3a (P < 0.001) in the target tissue of patients with increased ischemia time. CONCLUSIONS Given our results, C3a is a highly sensitive early indicator of ischemia-reperfusion damage. Our results give further insight into development of IRI after complicated FTT.

Fractionated Repetitive Extracorporeal Shock Wave Therapy: A New Standard in Shock Wave Therapy?

Background. ESWT has proven clinical benefit in dermatology and plastic surgery. It promotes wound healing and improves tissue regeneration, connective tissue disorders, and inflammatory skin diseases. However, a single treatment session or long intervals between sessions may reduce the therapeutic effect. The present study investigated the effects of fractionated repetitive treatment in skin microcirculation. Methods. 32 rats were randomly assigned to two groups and received either fractionated repetitive high-energy ESWT every ten minutes or placebo shock wave treatment, applied to the dorsal lower leg. Microcirculatory effects were continuously assessed by combined laser Doppler imaging and photospectrometry. Results. In experimental group, cutaneous tissue oxygen saturation was increased 1 minute after the first application and until the end of the measuring period at 80 minutes after the second treatment (P < 0.05). The third ESWT application boosted the effect to its highest extent. Cutaneous capillary blood flow showed a significant increase after the second application which was sustained for 20 minutes after the third application (P < 0.05). Placebo group showed no statistically significant differences. Conclusions. Fractionated repetitive extracorporeal shock wave therapy (frESWT) boosts and prolongs the effects on cutaneous hemodynamics. The results indicate that frESWT may provide greater benefits in the treatment of distinct soft tissue disorders compared with single-session ESWT.