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Biomedical subjects

M J Concannon

Publications and source records attributed to M J Concannon.

At least 19 recordsLinked to original sources
PubMed2000

The incidence of recurrence after endoscopic carpal tunnel release.

Endoscopic carpal tunnel release has been used to decompress the median nerve in carpal tunnel syndrome for over the past decade, with an advantage (over the traditional "open" release) being decreased pain in the postoperative period. The goals of this study were to attempt to define the recurrence rate after endoscopic carpal tunnel release and to determine if it differs from that of open technique. The charts of 191 consecutive carpal tunnel syndrome patients treated operatively at the University of Missouri were reviewed. For this study, recurrent carpal tunnel syndrome was defined as documented cases in which the symptoms had resolved following surgical release but subsequently recurred, requiring surgical rerelease of the carpal tunnel. All endoscopic releases were performed using the Chow two-portal technique. Statistical analysis was performed using Fisher's exact test. A total of 103 patient hands had open carpal tunnel releases; 88 were endoscopically released. Total follow-up time (from the initial release) averaged 29 months for the open group and 22 months for the endoscopic group. There were no recurrences in the open group and six recurrences in the endoscopic group (7 percent, p = 0.008). All six recurrences were in worker's compensation patients. The median time between endoscopic release and rerelease was 8.5 months. There seems to be a statistically higher incidence of recurrence of carpal tunnel syndrome after endoscopic release compared with the traditional "open" release in our cases. Although the pathogenesis of this increased rate of recurrence is not clear, this should be considered when planning surgical release of the volar carpal ligament for carpal tunnel syndrome.

Adult↗
PubMed1999

Workforce issues.

Explore the source record for details and available documents.

Forecasting↗
PubMed1999

Digital images in the diagnosis of wound healing problems.

The use of digital wound images could allow remote consultation among patients, physicians, or other care-givers located at quite distant sites by means of the Internet. To evaluate the efficacy and validity of digital images for the evaluation of wounds, the ability and reliability of surgeons to diagnose and make treatment suggestions using digital images of several types of wounds were compared. Twenty-four wound images on 35-mm slides were selected for use in this study. Each slide image was digitized at 24-bit color with a resolution of 640 pixels horizontal by 425 pixels vertical and stored as a JPEG file. These images were then presented as a slide show on a video monitor, with resolution set at 640 x 480. Six physicians examined the images, first in digital format and later in the original slide form. Each observer assessed each wound and possible treatment options by filling out a questionnaire using a series of yes/no questions. For all observers, there was an 87 percent agreement between digital and slide images (p = 0.004). The agreement between the digital and slide images was measured for each individual observer using a kappa coefficient. The agreement level corresponded to the experience of the observer, with the kappa values ranging from greater than 0.8 (almost perfect agreement) for the attending plastic surgeon to just greater than 0.5 (moderate agreement) for the intern. With this study, the feasibility of distance wound consultation using digital images of a quality consistent with consumer-grade digital photography was demonstrated.

Feasibility Studies↗
PubMed1999

The antibacterial effects of tumescent liposuction fluid.

Tumescent liposuction is currently one of the most commonly performed aesthetic procedures. Despite the variable use of preoperative antibiotics, infection is uncommon. Prior works suggest that the low incidence of infection may be due to lidocaine's antibacterial properties. However, these properties have only been demonstrated using concentrations of lidocaine above 0.8%, significantly higher than those used in tumescent liposuction. The purpose of this study was to determine if the commonly used tumescent fluid containing 0.1% lidocaine, 1:1000,000 epinephrine, and 0.012 mEq sodium bicarbonate possesses antibacterial activity. Using the broth microdilution method, the minimum inhibitory concentrations of Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and Group A beta-hemolytic Streptococcus were determined after exposure to either lidocaine, epinephrine, bicarbonate, or the combination of all three agents. To determine if there were significant growth differences not detectable by the broth microdilution method, bacterial concentrations were obtained through the use of a spectrophotometer, and significant differences from the controls were calculated by one-way analysis of variance. To determine if prolonged exposure to the tumescent mix would alter bacterial growth, a Killing Time study was also undertaken. The results indicated that the minimum inhibitory concentration of lidocaine was not less than 0.5% for any of the bacteria, whereas the lowest minimum inhibitory concentration of the combined solution was 0.25%. The lowest inhibitory concentration as determined by spectrophotometric analysis for the combined solution was 0.13% (p < 0.01). Analysis of the Killing Time data revealed no inhibition of bacterial growth over time. In conclusion, lidocaine, epinephrine, and bicarbonate do exhibit antibacterial properties at high concentrations. However, the commonly used tumescent mixture containing dilute concentrations of these agents does not significantly inhibit the growth of commonly encountered bacteria.

Anti-Bacterial Agents↗
PubMed1998

Late digital replantation failure: pathophysiology and risk factors.

It is generally accepted that replanted digits surviving at least 1 week following surgery rarely succumb to ischemic necrosis. Presented here are 2 patients who experienced late digital replantation failure. The first patient is an 8-year-old boy who had his index finger replanted at the proximal phalangeal level. After 16 days of viability, the replanted digit became swollen and subsequently necrosed. The second patient is a 35-year-old man with a history of smoking and intravenous drug use who underwent replantation of his avulsed thumb at the metacarpophalangeal joint. The replanted thumb was viable at the 2-week follow-up, but began to show ischemic changes at 3 weeks and eventually required revision amputation at the interphalangeal level. Both of these patients demonstrate late digital replantation failure--an unusual and poorly understood phenomenon. A discussion of possible risk factors and potential pathophysiology is presented.

Adult↗
PubMed1998

Wound coverage using modified tissue expansion.

We describe the use of a "lacing apparatus" across large and complex wounds to accomplish wound closure. This technique utilizes the principles of tissue expansion (exploiting inherent extensibility of the skin, mechanical creep, and biologic creep) but is able to employ them in situations in which traditional tissue expansion (utilizing implantable expanders) is not practical. After preparation, the wounds are laced with large nylon suture, which is tightened on a daily basis, typically allowing closure of even massive wounds within 8 to 10 days. In this report, we describe the technical details of wound preparation, application of the lacing apparatus, and postoperative execution of the expansion leading to final wound closure. This technique is particularly valuable in the upper arm, trunk, and lower extremity but has limited application in the distal forearm and the distal third of the lower extremity.

Adult↗
PubMed1998

Microsurgical replantation of an ear in a child without venous repair.

Ear amputation can leave a devastating deformity; the application of microsurgical replantation techniques has allowed very favorable aesthetic outcomes when successful. We report a case of ear replantation in a child in whom a venous repair was not performed; instead medicinal leeches were used to decompress the ear in the immediate postoperative setting. This represents the third reported case of successful ear replantation without microsurgical venous anastomosis. A review of the literature reveals the high incidence of venous congestion requiring external decompression (57 percent) and the very high rate of salvage (80 percent) after replantation. Surgeons attempting ear replantation should be aware of the high rate of ear survival in the situation of no venous outflow (with appropriate decompression techniques) and should not abandon attempts at replantation because of the inability to establish venous outflow microsurgically.

Bites and Stings↗
PubMed1997

Bone induction using demineralized bone in the rabbit femur: a long-term study.

While traditional bone grafting is the standard for replacement of segmental bony defects, alternative options (avoiding morbidity of autologous grafts) are attractive and continue to be sought. This study attempted to determine whether demineralized bone powder could be used reliably to replace a significant bony deficit at a weight-bearing site. The long-term functional characteristics of this induced bone were analyzed to determine whether it maintained its strength and shape and reacted normally to physiologic stress over an extended period of time (12 months). In 55 New Zealand White rabbits, a 1-cm length of femur was removed (approximately 20 percent of the total length of the rabbit femur). The femur was then reconstructed with a titanium mandibular plate, leaving the gap intact. In 38 of the animals, this gap was filled with demineralized bone powder in an attempt to induce bone to form across the defect. In group 1 (n = 23), the mandibular plate remained in place for the duration of the study (12 months). In group 2 (n = 15), the plate was removed 8 weeks after placement of the demineralized bone powder, and the animals were followed for an additional 12 months. In group 3 (n = 10), nothing was placed within the bony gap. In group 4 (n = 7), the gap was repaired with autologous bone graft. All the animals that received demineralized bone powder completely filled the osteotomy gap with new bone within 6 to 8 weeks after implantation. None of control group 3 formed bone across the gap (p < 0.001). Eighty-six percent of control group 4 (autologous bone graft) successfully formed bone across the osteotomy gap. In addition, 90 percent of control group 3 had hardware failure within 8 weeks after surgery compared with 0 percent (0 of 38) of the group that received demineralized bone powder (p < 0.001). In group 1, analysis after 12 months revealed that the bone formed ultimately became thin and easily fractured, most likely because of shielding from stress loading by the mandibular plate. In contrast, in group 2 (in which the plate was removed after 8 weeks), the bone remodeled and hypertrophied in response to the physiologic stress of weight bearing and at the end of the 12-month period was essentially identical to normal femur. In certain circumstances, reconstruction of bony defects using bone-induction techniques may be as good as autologous bone grafting, with the advantage of limiting the donor-site morbidity for the patient.

Animals↗
PubMed1997

The predictive value of electrodiagnostic studies in carpal tunnel syndrome.

In recent years, electrodiagnostic studies have become an expected component in the work up and evaluation of carpal tunnel syndrome. We conducted a retrospective review of 460 carpal tunnel decompressions to determine whether the accuracy of diagnosis and the prediction of therapeutic outcome could be related to the positivity and severity of findings on preoperative electrical studies. The 349 patients (460 hands) were divided into two groups: group 1 consisted of hands with the clinical diagnosis of carpal tunnel syndrome but with normal electrodiagnostic studies (n = 62); in group 2 the hands had a clinical diagnosis of carpal tunnel syndrome with confirmatory electrodiagnostic studies (n = 398). The number and distribution of signs and symptoms of carpal tunnel syndrome were not statistically different between these two groups. There was not a statistically significant difference in the success rate of surgery or the incidence of complications. The similarities between these two groups suggests that the distinction between them (the positivity of electrodiagnostic studies) is an artificial one and that the clinical diagnosis of carpal tunnel syndrome is sufficient to predict the presence of the disease, as well as outcome of surgery. On the basis of these data, strict adherence to electrodiagnostic studies to confirm the diagnosis will exclude 13 percent of the patients with legitimate carpal tunnel syndrome from receiving appropriate therapy.

Adult↗
PubMed1996

Late rupture of a flexor tendon after electrical injury: tendon localization using magnetic resonance imaging. A case report.

Rupture of a flexor tendon in the nonrheumatoid population is rare. Localizing the level of the tendon rupture can be a difficult task. We describe an individual who presented with the sudden inability to flex the index finger of the hand, which had been subjected to a severe electrical injury. Physical exam demonstrated lack of index finger flexion at the distal joint. The patient denied any pain or history of recent trauma. Preoperative magnetic resonance imaging (MRI) successfully located the proximal and distal ends of the ruptured flexor digitorum profundus tendon in the forearm. MRI allows for accurate preoperative assessment of tendon position and degree of retraction, thereby facilitating surgical planning and approach. Accurate localization of tendon pathology preoperatively minimizes unnecessary dissection, shortens the operative procedure, and clarifies operative planning.

Arm Injuries↗
PubMed1996

Is there liability with chemotherapy following immediate breast construction?

Review of 46 consecutive patients undergoing immediate breast reconstruction with tissue expanders and subsequent implant placement was conducted to assess the potential liability of adjuvant chemotherapy. Twenty-three patients required chemotherapy, while 23 did not. Critical comparison of complications and outcome of the two groups revealed no significant differences. Within the parameters of the study (avoidance of expansion or surgery during the period of chemotherapy), there appeared to be no disadvantage posed to the immediate reconstruction patient by adjuvant chemotherapy. We feel that this option can continue to be offered despite the anticipation of probable chemotherapy.

Breast Implants↗
PubMed1995

The use of demineralized bone powder in an onlay graft model.

Demineralized bone powder has been shown previously to successfully induce bone formation. The purpose of this study was to use demineralized bone powder in an onlay graft situation using implantable molds. Demineralized bone powder was placed within a mold and rigidly attached to the frontal bones of 30 New Zealand White rabbits by screw fixation. Periosteum was not closed over the mold. A control group had the mold placed without demineralized bone powder used. After 12 weeks of growth, the animals were sacrificed and the frontal bone was analyzed for bone growth using standardized histology and fluorescent microscopy. One hundred percent of the animals (30 of 30) that received demineralized bone powder underwent bone growth in the precise shape of the mold (p < 0.001). There was no new bone development in the control group (n = 8). Placement of larger molds duplicated these results (n = 20) with a 650 percent increase in frontal bone thickness within 12 weeks after placement of demineralized bone powder. This model mimics onlay bone grafting, and perhaps this technique may replace onlay grafting or alloplastic implantation in certain circumstances, avoiding the extra morbidity and donor-site defects associated with bone grafting.

Animals↗
PubMed1993

Free fibular transfer in a growing individual (long-term results).

We present a case report of a 4-year-old in whom the distal fibula and epiphyseal plate had been traumatically destroyed. A free vascularized epiphyseal transfer using the ipsilateral proximal fibula was performed which provided good bony stability at the ankle, as well as excellent long-term growth characteristics. We demonstrate immediate postoperative results, as well as long-term (5 years) follow-up.

Bone Transplantation↗
PubMed1993

Inhibition of perioperative platelet aggregation using toradol (ketorolac).

Traditionally, aspirin is used as an inexpensive and usually well-tolerated agent to accomplish inhibition of platelet aggregation after microvascular surgery. Occasionally, however, aspirin is contraindicated. We have successfully used Toradol (ketorolac) after microvascular tissue transfer to inhibit platelet aggregation postoperatively, and documented this in our laboratory. We present two individuals on our surgical service requiring microvascular free tissue transfer with documented allergic reactions to aspirin. Platelet function was successfully suppressed while on the Toradol regimen, and this function returned to normal within 24 hours after stopping this therapy. We believe this agent may have some use for the microvascular surgeon for the population of patients in which aspirin is contraindicated or difficult to administer.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1993

An intraoperative stent for McIndoe vaginal construction.

We report an inexpensive, easy-to-apply vaginal stent for use in McIndoe vaginal reconstruction using Surgi-Stuf inserted in a sterile condom. This material's easy compressibility and good "memory" facilitate good apposition for the skin grafts while being easily placed into the depth of the new vaginal pocket.

Congenital Abnormalities↗