Moebius syndrome: the new finding of hypertrophy of the coronoid process.

The first detailed description of congenital facial paralysis was reported by Moebius in 1888. It is characterized by either unilateral or bilateral paralysis of the facial muscles and an associated abducens palsy. The present report is of two patients with Moebius syndrome, who were also diagnosed with trismus at birth. Each patient also demonstrated bilateral hypertrophy of the coronoid process of the mandible. In effect, the zygoma obstructed the excursion of the mandible because of a "coronoid block." A three-dimensional computed tomography scan demonstrated normal temporomandibular joints but bilateral hypertrophy of the coronoid processes and micrognathia. Both patients demonstrated less than 10 mm of oral excursion. Bilateral coronoidectomies were performed through an intraoral approach. The oral excursions after surgery increased to at least 20 mm. In each of these patients, the coronoid process was enlarged relative to the zygoma, which was of normal size and configuration. The trismus was associated with blocking of the coronoid by the anterior zygoma, preventing open or full excursion of the hypoplastic mandibles. Moebius syndrome can have a variable presentation at birth. In two patients, the authors describe a new finding of hypertrophy of the coronoid process and trismus secondary to obstruction of the coronoid by the hypertrophic zygomas during oral excursions. Each patient is described, and a review of the literature is discussed.

Omental transfer to the brain: an experimental study in hydrocephalic rabbits.

Hydrocephalus is a common and potentially lethal condition in children that results from an imbalance between absorption and production of cerebral spinal fluid (CSF). Silastic shunts are inserted to drain excess CSF, but they are prone to a number of problems, and at times may be unreliable and ineffective. This study examines the physiological basis of a pedicled omental transfer to the brain as a functional conduit for CSF in an experimentally induced hydrocephalic rabbit model. The ability of the omentum to transport CSF from the subarachnoid space was tested using radioactive tracer substances: radio-iodinated serum albumin (125I-RISA), chromium 51-ethylenediaminetetraacetate (51Cr-EDTA), and technetium 99m (99mTc) glucoheptonate. Immediate ability of exteriorized omentum to transport artificial CSF, as well as transposed omental transport of subarachnoid CSF at 1 month, were examined. Nuclear scan measurements were correlated with clinical observation and a double-blind histological analysis with trichrome and hematoxylin-eosin stain. Exteriorized omentum rapidly absorbed 99mTc glucoheptonate-labeled artificial CSF, with a rapid appearance in the systemic circulatory and urinary systems. Transposed omentum to the brain in animals with artificially created hydrocephalus showed evidence of CSF-labeled 125I-RISA and 51Cr-EDTA absorption in those animals demonstrating histologically viable omentum.

The molecular basis of keloid and hypertrophic scar formation.

Excess scar formation secondary to traumatic or surgical injuries can have devastating consequences, ranging from body disfigurement to organ dysfunction. Hypertrophic scars and keloids are skin fibrotic conditions that can be caused by minor insults to skin, such as acne or ear piercing, or by severe injuries such as burns. Differences between keloids, hypertrophic scars and normal scars include distinct scar appearance, histologic morphology and cellular function in response to growth factors. Recent advances in our understanding of the wound healing process reveal possible causes for hypertrophic scars and keloids. This information might assist in the development of efficacious treatment for hypertrophic scar and keloid formation.

Elevated levels of plasminogen activator inhibitor-1 may account for the altered fibrinolysis by keloid fibroblasts.

Using a 3-dimensional fibrin gel model system simulating fibroplasia of wound repair, we investigated the interaction between keloid fibroblasts and fibrin matrix and compared it with that of normal fibroblasts. Normal skin fibroblasts caused fibrin gel degradation under serum-free conditions, whereas keloid fibroblasts did not cause microscopically detectable gel degradation. Fibrin gel degradation occurred through plasmin-mediated fibrinolysis, which was initiated by fibroblasts exhibited high uPA but low plasminogen activator inhibitor-1 (PAI-1) activities, and transforming growth factor-beta 1 prevented fibrinolysis of normal fibroblasts by upregulating PAI-1 while downregulating uPA activities. In contrast, keloid fibroblasts exhibited an intrinsically high level of PAI-1 and a low level of uPA. This change in the ratio of activator and inhibitor activities was attributed to altered fibrin degradation by keloid fibroblasts. The PAI-1 increase was also demonstrated at the RNA level by Northern analysis. In terms of the pivotal role of the plasmin/plasminogen activator system in matrix remodeling, the elevated PAI-1 level exhibited by keloid fibroblasts may have significant consequences not only in altered fibrin degradation, but also in subsequent repair steps that lead to keloids and fibrosis.

The physiologic basis for nonconventional vascular perfusion.

It is traditionally thought that the exchange of oxygen occurs only at the capillary level, with both arterial inflow and venous outflow required. However, as early as 1970, studies have indicated that significant arteriolar and venular diffusion of O2 and CO2 occurs. The precapillary and postcapillary diffusion of oxygen and carbon dioxide and their potential regulation via the Bohr effect are key elements in understanding the success of nonconventional vascular perfusion (arterialized venous, total arterial, total venous), where the capillary circulation is bypassed. In retrograde "reverse-flow" island flaps, there is an anterograde blood flow through the capillary bed, with nonconventionally reversed flow within the arterial and venous systems, respectively. The reversal of venous flow is best explained as a combination of valvular insufficiency and the existence of vein-vein bypass channels via the venae comitantes.

Debridement of bacterial and particulate-contaminated wounds.

Debridement of contaminated wounds is an essential component of uncomplicated wound healing. Efficient techniques should be capable of removing bacteria as well as foreign matter because of the well-known ability of foreign bodies to potentiate infection. We have compared the ability of current debridement techniques with the relatively new ultrasound debridement to clean wounds contaminated with bacteria and particulate matter. In part I, we prepared dorsal wounds on 15 Sprague-Dawley rats, and 20 mg of Montmorillonite clay soil fraction, a well-known infection-potentiating factor, was placed in each wound. Animals were randomly assigned to one of three treatment groups: ultrasound debridement, soaking, and irrigation. The amount of clay removed from each wound was measured. In part II, 48 Sprague-Dawley rats were given a standard wound and inoculated with a subinfective dose of Staphylococcus aureus bacteria and 10 mg of Montmorillonite clay particles. Each rat was randomly assigned to a debridement technique--soaking, scrubbing, high-pressure irrigation, and ultrasound--and was examined after 7 days for inflammatory responses. Results of part I demonstrated that ultrasound debridement and irrigation remove statistically equal amounts of clay (p < 0.05). In part II, we found that high-pressure irrigation and ultrasound debridement effectively treat contaminated wounds (gross infection, p < 0.05; wound induration, p < 0.0001; bacteria counts, p < 0.002). This study presents ultrasound debridement as effective treatment of contaminated wounds.

Modulation of collagen synthesis by transforming growth factor-beta in keloid and hypertrophic scar fibroblasts.

Keloid and hypertrophic scars are fibrous growths characterized by overabundant collagen deposition. We examined the effect of transforming growth factor-beta (TGF-beta), a known stimulant for the production of connective tissue matrices, on the rate of collagen synthesis in keloid fibroblasts (KFs), hypertrophic scar fibroblasts (HSFs), and normal skin fibroblasts (NSFs). Fibroblasts were cultured in three-dimensional fibrin-gel matrices in the presence or absence of TGF-beta (5 ng/ml) or anti-TGF-beta neutralizing antibody (50 micrograms/ml). Secreted collagen levels, labeled with 3H-proline, were measured after 48 hours. KFs produced up to 12 times more collagen than NSFs, and up to 4 times more than HSFs. Although KFs increased their rate of collagen production by up to 2.7 times in response to TGF-beta, HSFs and NSFs did not (p = 0.065). Anti-TGF-beta antibody reduced the rate of collagen synthesis of KFs by 40% (p = 0.003), although it did not suppress collagen production in HSFs (p = 0.06) and NSFs (p = 0.75). We conclude that although KFs and HSFs are similar in that they both overproduce collagen, they are different in that only KFs display a marked sensitivity to TGF-beta, which is abundant during the proliferative phase of wound healing.

Comparison of various delivery systems for demineralized bone matrix in a rat cranial defect model.

Demineralized bone matrix (DBM) has been successfully used as a substitute for bone grafting. Autogenous bone grafts may cause site morbidity and undergo significant resorption. DBM may overcome these problems, but it has no mechanical stability until bone formation has occurred. We tested various alloplastic implants (i.e., Surgicel, polydioxanone [PDS], porous polyethylene [Medpor], and Gelfoam) in combination with DBM and compared it with DBM alone in a 9 x 9 mm rat cranial defect model. Histological and biomechanical measurements were performed at postoperative month 2. Among the study groups, Gelfoam/DBM inhibited bone formation to varying degrees and was the only group that displayed an inflammatory response. Mechanical pushout tests using a servohydraulic testing frame were conducted. The Medpor/DBM implant displayed the strongest support at 2 months; maximum load was 95% of intact skull. Surgicel/DBM and DBM alone were comparable; maximum load was 66% of intact skull. Gelfoam/DBM and PDS/DBM displayed the weakest support (48% of intact skull). We conclude that, after 2 months of implantation, alloplastic/DBM composites provide osseous structural integration. Gelfoam/DBM is not an effective delivery system for DBM in our model.

Emergent reuse leech therapy: a better method.

Tissues threatened by venous congestion often can be saved by timely leech therapy. Methods to restimulate sated leeches, particularly emergently, are only poorly described in the nineteenth-century literature. Sated leeches were purged of their blood meals by (1) posterior crop incision, (2) hypertonic saline (3 percent) immersion, (3) gentle finger pressure emesis, or (4) wood ash exposure. Their ability to reattach and refeed with or without serotonin stimulation was evaluated. All 20 leeches (100 percent) purged by posterior crop incision reattached, with 75 percent refeeding. After purging again, 87 percent of these refed leeches reattached, with 46 percent refeeding for a third time. Those leeches which did not initially refeed were exposed to serotonin 10 microM with 100 percent reattaching and 40 percent refeeding. None of the leeches purged by hypertonic saline immersion regurgitation reattached or refed. A single leech purged by finger pressure emesis reattached (20 percent) but did not refeed. After exposure to serotonin, two (40 percent) of each saline and finger pressure group reattached, with neither of the hypertonic saline group refeeding, while both finger pressure-purged leeches refed, consuming a meal 38 percent (+/- 29 percent) of original meal. None of those leeches which refed would reattach or refeed a third time. None of the wood ash-purged leeches reattached or refed even with serotonin exposure. The best method of purging leeches of their blood meals for emergent reuse is by posterior crop incision. Additional refeeding behavior can be achieved by immersion in serotonin 10 microM for 20 minutes.

Ultrasound debridement of trabeculated bone: effective and atraumatic.

Given the plethora of techniques available for debridement of contaminated bone, no single method can be considered ideal. Ultrasound has been shown to be less traumatic and more effective for debridement of contaminated soft tissue than either abrasive scrubbing or high-pressure jet irrigation. Using the distal femur and condyle of 23 freshly sacrificed adult Sprague-Dawley rats, this study was undertaken to compare ultrasonication to traditional debridement techniques in (1) their effectiveness in decontaminating trabeculated bone, (2) the subsequent effect of each treatment on bone cell function as measured by protein synthesis, and (3) the direct mechanical effects of each technique on the integrity of the bone structure itself. Ultrasonic debridement was found to be as effective as high-pressure jet irrigation or surgical scrubbing in debridement of contaminated trabeculated bone (no significant statistical difference). Overall activated bone cell function 24 hours after each debridement technique also was found to be equivalent (no significant statistical difference). However, electron microscopy reveals radical structural alterations of the bone after high-pressure jet irrigation or abrasive scrubbing that are not seen with ultrasound debridement. Acutely, the devastating effects of abrasive scrubbing and high-pressure jet irrigation leave an exposed bone matrix not only devoid of any cells but also honeycombed with interstices for entrapment of bacteria and other contaminants. All three debridement methods leave the deeper bone cells viable, but only ultrasound maintains the integrity of the directly involved bone trabeculum to reduce contamination, prevent colonization, and decrease possible infection.

Evaluation of a temporary arteriovenous shunt to establish neovascularization in a musculocutaneous flap: an experimental study.

On the dorsum of adult Sprague-Dawley rats, 3 x 7 cm pedicle flaps were raised and a temporary arteriovenous shunt (AVS) from anastomosis of the tail artery and vein was placed beneath. Fourteen, 21 and 28 days later, the pedicle flaps were converted to island flaps leaving only the AVS attachment. The degree of subsequent flap viability was directly related to the amount of time before flap conversion. At 14, 21 and 28 day intervals, there was 33.4%, 73.5% and 98% flap viability, respectively. Long-term AVS patency was found not to be required for flap survival. Normal hair growth, quantity and quality, occurred in only the 28 day delay group. Microangiography and histologic examination revealed extensive neovascularization from both the AVS artery and vein extending into the muscle, subcutaneous tissue and skin layers of each island flap. In summary, neovascularization of a large random pattern musculocutaneous island flap is possible using a temporary arteriovenous shunt. Flap survival is directly related to the length of time between AVS placement and cutaneous pedicle division, although long-term AVS patency is not required for continued flap viability. Hair growth may directly reflect the degree of underlying neovascular maturation. This AVS neovascularization technique could be applied to create new donor sites for free tissue transfer.

Chest-wall reconstruction for spondylocostal dysostosis.

A child with respiratory insufficiency due to a lethal syndrome known as spondylocostal dysostosis is described. Severe chest-wall deformities with resultant paradoxical chest-wall motion were successfully corrected by surgical reconstruction of the right thorax. We conclude that patients with the severe lethal form of the syndrome may benefit from aggressive surgical correction of the thoracic abnormality.

Reconstructive considerations for limb salvage surgery.

Tumors in the musculoskeletal system are generally treated surgically, although radiation therapy and chemotherapy have greatly improved survival statistics of patients with high-grade sarcomas of the musculoskeletal system. The mainstay in treatment of nearly every primary tumor of the musculoskeletal system is surgical resection for cure. Radiation therapy and chemotherapy continue to be important adjuvants in the overall management of musculoskeletal tumors. Functional limb salvage following radical resection is now possible in most resectable cases by placement of an alloplastic prosthesis, homograft, or autogenous bone for skeletal reconstitution, followed by well-vascularized soft-tissue coverage.

The biomechanical efficacy of an oscillating K-wire driver.

A new oscillating drill, designed for insertional ease and safety, was biomechanically tested using an MTS 812 servohydraulic material testing machine (Instrom). Holding strength and drilling force were compared against a traditional rotary drill using rabbit tibias to approximate the diameter and cortical thickness of human metacarpals. Three differently sized (0.028-, 0.045-, and 0.062-in. diameter) K-wires were evaluated for each drill. Mean peak axial load (drilling force) was significantly different for each wire driver type in each of the three sized K-wires (p < or = 0.01). The oscillating drill used an average of 3 N less force to penetrate either cortex. Mean peak pull-out force (holding strength) was higher for the oscillating drill, but the difference was not significant (p > or = 0.5). This study indicated that the oscillating drill required less force for insertion and had a similar holding strength as the rotary drill. In addition, our drill has been shown to be less damaging to surrounding soft tissues. This new type of drill is likely to be advantageous in the fields of hand, microsurgery, orthopedic, and plastic surgery, where bone fixation is often near vital neurovascular structures.

Demineralized bone matrix polydioxanone composite as a substitute for bone graft: a comparative study in rats.

Demineralized bone matrix (DBM) has been successfully used as a substitute for bone grafting. Autogenous bone grafts (ABG) may cause donor site morbidity and undergo significant resorption. DBM may overcome these problems but is mechanically unstable when originally placed. We explored using a slowly resorbable template, polydioxanone (PDS), in combination with DBM and compared it to ABG in a rat 9 x 9 mm cranial defect model. After both 1 and 3 months, histologically and biochemically well-formed bone was present in ABG/PDS and DBM/PDS-treated defects, but not in control defects (PDS alone). Mechanical push-out tests using a servohydraulic testing frame were conducted. Maximum load before failure of DBM/PDS increased from 65% at 1 month to 100% of that of intact skull at 3 months. In contrast, ABG/PDS was 50% as strong as DBM/PDS and not significantly stronger than PDS alone. ABG/DBM did not significantly increase in strength from 1 to 3 months. We conclude that DBM/PDS is better than ABG/PDS in treating cranial defects in the rat model, and that an absorbable osteoinductive bone substitute with superior mechanical advantage is possible without the disadvantages of ABG.

Restoration of venous outflow by simultaneous creation of an arteriovenous shunt and pedicle flap using a rat model of foot replantation.

Replantation of amputated rat feet utilizing an efferent arteriovenous shunt constructed between the distal posterior tibial artery and the proximal posterior tibial vein, in the absence of all other venous drainage, provides an alternative pathway to the normal venous drainage in a replanted rat foot. However, this substitute venous drainage was insufficient to prevent progressive ischemia and necrosis of some or all of a replanted rat foot. When a cutaneous pedicle flap supplemented the arteriovenous shunt, venous drainage was much improved, tissue hypoxia and edema began to subside on the third day, severe tissue necrosis was prevented, and seven of eight feet replanted by this technique survived. These observations may be useful in replantation in humans when veins in the amputated part are too small to be used or so damaged that they cannot be repaired or reconstructed by a vein graft, but arteries can still provide a means of returning blood from the amputated part. Constructing an alternative pathway to the normal venous drainage pattern may allow severely damaged parts to survive after replantation.

Expanding the limits of composite grafting: a case report of successful nose replantation assisted by hyperbaric oxygen therapy.

A successful nose replantation assisted by hyperbaric oxygen therapy is presented, with a brief discussion of the possible mechanisms and a brief literature review of the use of hyperbaric oxygen in tissue preservation and replantation. Although it is not certain that the hyperbaric oxygenation ensured the survival of the replanted nose in this 2-year-old girl, there was documented change in graft appearance during the initial hyperbaric oxygen treatment. A 1-month, 1-year, and 2-year follow-up is included.

Leech therapy: when once is not enough.

Venous congestion is a constant threat in the survival of free flaps, pedicled flaps, tissue replantations and traumatized tissue. Leech therapy has proved effective in salvaging much of these compromised tissues. To be effective, leeches must be both readily available and hungry, requirements not always easily met. Our investigation seeks to establish a means to return sated leeches to their previous unfed, hungry state for reuse. Sated leeches were purged of their blood meals by placement in 3% hypertonic saline or by gentle finger pressure, then exposed to serotonin 0 microM (control), 10 microM, 30 microM or 90 microM for 20 min. Subsequent rebiting/refeeding was observed and analysed. Leeches bathed in serotonin rebit or reattached at nearly four times the rate of unexposed leeches; 30% vs 8% respectively. Biting, however, is not refeeding. Overall, 41 leeches were treated with serotonin with four (10%) refeeding. Those that refed consumed a significantly smaller blood meal than the initial feeding; 50% +/- 47% SD vs 348% +/- 143% SD of original body weight. None of the control group refed. As a method for routinely reusing leeches, serotonin bathing cannot be recommended. In the immediate postoperative period with the sudden emergence of venous congestion requiring leech therapy, but with an inadequate number available, this 20% [corrected] refeed rate after 10 microM serotonin exposure could potentially determine the success or failure of the flap/replantation until fresh leeches are made available.