Stefan M. Lemperle

BONE RESPONSE TO IMPLANT SURFACE MORPHOLOGY

This study was designed to measure implant osseointegration using different surface treatments. Bilateral distal intramedullary implantation of titanium cylinders 25 mm x 5 mm was performed in 60 rabbits. The 3 surfaces tested were fiber mesh, mean pore size 400 microns; grit-blasted, mean surface roughness 6 microns; and acid-etched, mean surface roughness 18 microns. Scanning electron microscopy was used to measure the percentage of the surface of each implant in contact with bone at 2, 6, and 12 weeks postimplantation. Mechanical pull-out testing of the bone-implant interface was performed at 12 weeks. Overall, acid-etched surfaces demonstrated greater mean osseointegration than fiber mesh surfaces. All 3 surfaces demonstrated similar interface strengths. Acid etching has potential as a means of enhancing bony apposition in cementless fixation.

Nail regeneration by elongation of the partially destroyed nail bed.

&NA; Patients with partially destroyed fingernails tend to hide them, and such patients often do not find help because fingernails are considered of little functional value. To improve the aesthetic appearance of such nails, a simple excision of the destroyed nail matrix can stimulate the growth of the residual healthy matrix and regenerate the nail. Prerequisite is a healthy nail residue of at least the lunula. An excision of an en bloc, crescent‐shaped, full‐thickness scar, 5 mm at its greatest width and extending from one lateral nail fold to the other, increases the length of the nail plate. Together with the matrix, the nail will grow about 4 mm distally. A second crescent‐shaped excision 1 to 2 months later will further lengthen the nail until it has gained full length. Normal nail growth was achieved in 11 patients who had partially scarred nail beds after mycosis or trauma. (Plast. Reconstr. Surg. 111: 167, 2003.)

The direction of optimal skin incisions derived from striae distensae.

Background: In an effort to achieve inconspicuous scars, plastic surgeons try to place their incisions in established creases and folds of skin. Although well established in the face and abdomen, these folding lines are often disputable on other parts of the body. Striae distensae always develop perpendicular to lines of tension, and their direction can be used to determine optimal incision lines. Methods: The authors examined photographs of 213 individuals with striae, and a composite diagram was created. This composite along with descriptions of Langer lines, Pinkus main folding lines, and Kraissl lines were compared with a clinical scar revision database and 276 images of incisions and scars from the Internet. Results: Pinkus described the main folding lines in 1927 and Kraissl in 1951 recommended that incision lines be placed perpendicular to the direction of underlying muscles. Both references bear some similarities to what we noted in our composites. In comparison, Langer lines, although of historical interest, poorly predicted the direction of optimal skin incisions. Conclusions: The optimal direction for surgical skin incisions should take into strong consideration patterns defined by nature’s striae distensae, which always develop perpendicular to skin tension lines. Main folding lines can be used as guides when addressing or refining problem scars and similarly facilitate surgical planning of elective incisions, which may prevent problem scar formation for our patients.

Endoscopic lower esophageal sphincter bulking for the treatment of GERD: safety evaluation of injectable polymethylmethacrylate microspheres in miniature swine

BACKGROUND Endoscopic therapy for GERD is an appealing, minimally invasive alternative to medical treatment and surgery. Various materials have been tested to augment the lower esophageal sphincter (LES), with limited success. To our knowledge, safety and migration of polymethylmethacrylate (PMMA) microspheres has never been evaluated. OBJECTIVE To assess the safety, migration, inflammatory reaction, and durability of PMMA injected into the LES of miniature swine to create a reflux barrier. DESIGN Animal study. SETTING Approved animal research facilities. INTERVENTION Injection of the LES of miniature swine with PMMA. Histopathology of the injected site at certain intervals and postnecropsy microsphere counts of various organs. MAIN OUTCOME MEASUREMENTS Minimal inflammatory reaction at the injection site, persistent bulking effect of the material, and no migration of microspheres. RESULTS Injection of LES with PMMA caused a mild inflammatory reaction. The bulking effect of the injected material was persistent. Migration of microspheres was eliminated with the use of larger-sized microspheres. LIMITATIONS Animal model. CONCLUSION Our phase I study documented that 40-microm polymethylmethacrylate microspheres are biocompatible and that PMMA microspheres are resistant to degradation when injected submucosally into the wall of the esophagus. The detection of 40-microm PMMA microspheres in local lymph nodes, liver, and lungs of some animals in the phase I study clearly documented transport of PMMA away from the injection site. This finding was eliminated by increasing the size of microspheres to 125 microm. The potential therapeutic effects of these larger microspheres for humans with GERD remains to be evaluated.

Urethral bulking with polymethylmethacrylate microspheres for stress urinary incontinence: tissue persistence and safety studies in miniswine.

OBJECTIVES To evaluate the safety and persistence of injectable polymethylmethacrylate (PMMA) microspheres as a long-lasting urethral bulking agent in pigs. PMMA microspheres of 2 different diameters (40 and 125 μm) were tested to investigate the potential for migration and dislocation after injection. A similar product containing 40-μm PMMA microspheres has been used as an injectable wrinkle filler for >25 years and received Food and Drug Administration approval in 2006 (ArteFill). METHODS A total of 22 female pigs received 4 submucosal implantations of PMMA microspheres, using either a cystoscope or a newly developed urethral injection device (UroScope). At death and necropsy at 8 days and 1, 3, and 6 months, the urethral injection site, liver, lung, spleen, and pelvic and iliac lymph nodes were processed for histologic examination and microsphere count using organ dissolution and microscopy. RESULTS All injected submucosal blebs were still present at 6 months and showed no signs of inflammation. Tissue dissolution of the local lymph nodes and major organs demonstrated the transport of some of the 40-μm microspheres to the local lymph nodes and lung but not to the liver or spleen. In contrast, no 125-μm microspheres were detected in any distant organ. CONCLUSIONS The submucosal implantation of 125-μm PMMA microspheres into the urethra provided a safe and persistent bulking effect in pigs. The positive results of the present study encourage additional investigation of 125-μm PMMA microspheres as a long-lasting bulking agent for the treatment of female stress urinary incontinence. Furthermore, a newly developed urethral injection device (UroScope) proved beneficial and cost-effective to facilitate the transurethral injections of 125-μm PMMA microspheres.

Osteoplastik ausgedehnter Kieferdefekte mittels geschützter Knochenregeneration unter Anwendung großporiger resorbierbarer Folien

Die vorgestellte Studie hat zum Ziel, durch geschützte Knochenregeneration eine vereinfachte Methode der Kieferrekonstruktion zu etablieren. Durch die Verwendung einer großporigen resorbierbaren Folie werden ein Weichteilprolaps in Knochendefekte und eine Druckatrophie des transplantierten Knochens vermieden. Durch die Verwendung einer druckresistenten, resorbierbaren, makroporösen Folie werden die Vorteile der geschützten Knochenregeneration unter Verwendung resorbierbaren Materials eingesetzt. Die makroporöse Struktur erlaubt die Einsprossung von Kapillaren aus den umgebenden Weichgeweben und dient daher der schnelleren Knochenregeneration. Die verwendete Folie besteht aus einem 70:30-Poly(L-co-DL)-Laktid mit thermoplastischen Eigenschaften und dient in der vorgestellten Studie der Aufnahme von gemahlener, autologer Spongiosa. In der Pilotstudie wurde diese Rekonstruktion bei 7 Patienten mit Unterkieferdefekten vorgenommen. Teilweise handelte es sich bei diesen Defekten um Kontinuitätsdefekte, die nach Tumor- oder Zystenentfernungen entstanden sind. Nach festgelegtem Studienprotokoll wurde die knöcherne Regeneration durch Röntgenkontrollen überprüft. Die bisher positiven Erfahrungen haben eine multizentrisch angelegte Untersuchung mit geplanten 50 Patienten an 5 Universitätskliniken veranlasst. In weiteren Schritten ist eine Füllung des Containers mit osteokonduktiven bzw. osteoinduktiven Substanzen geplant, um die Entnahme der autologen Spongiosa zu vermeiden. This study was performed to demonstrate a protected bone regeneration method using macroporous resorbable sheets for the treatment of extended lower and upper jaw defects. By applying mechanical protection of bony defects with, e.g. membranes or titanium mesh, soft tissue prolapse as well as pressure on bone transplants which contributes to partial resorption can be avoided. The use of a pressure-resistant, resorbable, macroporous sheet combines the advantage of protected bone regeneration and complete resorption of the implanted sheet. The macroporous structure facilitates capillary ingrowth from the surrounding soft tissue. The sheet is made of 70 : 30 Poly(L-co-DL)-lactate with thermoplastic character and can be used as a container for autologous spongiosa or other osteoinductive and -conductive bone graft substitutes. In a pilot study, seven patients with lower jaw defects resulting from large cysts or tumor resections, some affecting the continuity of the mandible, were treated with this method. Following a protocol, X-rays were obtained to document the bony regeneration. The positive experience with this pilot study encouraged a multicenter project involving five university hospitals and 50 patients. The application of resorbable sheets in combination with transplantation of mersilized autologous spongiosa is currently being investigated. In future studies, fillings of sheets with osteoconductive and -inductive materials are planned.This study was performed to demonstrate a protected bone regeneration method using macroporous resorbable sheets for the treatment of extended lower and upper jaw defects. By applying mechanical protection of bony defects with, e.g. membranes or titanium mesh, soft tissue prolapse as well as pressure on bone transplants which contributes to partial resorption can be avoided. The use of a pressure-resistant, resorbable, macroporous sheet combines the advantage of protected bone regeneration and complete resorption of the implanted sheet. The macroporous structure facilitates capillary ingrowth from the surrounding soft tissue. The sheet is made of 70:30 Poly(L-co-DL)-lactate with thermoplastic character and can be used as a container for autologous spongiosa or other osteoinductive and -conductive bone graft substitutes. In a pilot study, seven patients with lower jaw defects resulting from large cysts or tumor resections, some affecting the continuity of the mandible, were treated with this method. Following a protocol, X-rays were obtained to document the bony regeneration. The positive experience with this pilot study encouraged a multicenter project involving five university hospitals and 50 patients. The application of resorbable sheets in combination with transplantation of mersilized autologous spongiosa is currently being investigated. In future studies, fillings of sheets with osteoconductive and -inductive materials are planned.