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Biomedical subjects

M D Wells

Publications and source records attributed to M D Wells.

At least 19 recordsLinked to original sources
PubMed2003

Reconstruction of nasal defects using modified composite grafts.

Nasal defects in certain areas such as the columellar-lobular junction, the alar rim and the soft triangle are cosmetically challenging to reconstruct. This paper describes a technique that enables the use of composite grafts for these specific nasal defects. Termed modified composite grafts (MCG), they involve creation of a dermal pedicle on the graft that enlarges the surface area of contact between the graft and the recipient bed. In addition, we used postoperative surface cooling for grafts larger than 1.5cm. Both these modifications allow reconstruction of defects larger than 1.5cm, improve graft survival and yield a better cosmetic outcome. Using representative cases from our series of 50 patients, we demonstrate that MCGs provide a simple, single-staged alternative to otherwise complex reconstruction of specific areas of the nose. They offset the need for local flaps, avoid donor-site scars and yield excellent long-term results.

Basal Cell Carcinoma↗
PubMed2000

Reconstruction of the burned breast.

Fundamental principles of management of breast burns begin with recognition and preservation of any viable breast bud tissue. Reconstruction begins when the burned breast envelope is insufficient to allow unrestricted breast development. Complete contracture release is obtained by incision or excision of the restricting burn scar and thick split-thickness grafting. Occasionally, breast mound reconstruction with regional musculocutaneous flaps or tissue expanders is necessary. Balancing procedures, such as reduction or mastopexy of an opposite unburned breast, are often helpful. After a period of 6 to 12 months of compression garments, scar management, and settling, nipple-areola reconstruction is undertaken and consists of a combination of local flaps, full-thickness grafting, or composite grafts tailored to each patient's needs. Long-term follow-up is necessary to ensure that breast development continues satisfactorily and that contractures do not recur.

Adolescent↗
PubMed1999

Incidence and sequelae of nocturnal respiratory obstruction following posterior pharyngeal flap operation.

A competent velopharyngeal mechanism is important for the production of normal speech, and the secondary procedure of a posterior pharyngeal flap (PPF) may be necessary in some patients to achieve this goal. A number of complications have been described in the literature following pharyngeal flap surgery. The purpose of this study was to examine short- and long-term complications after PPF surgery, and in particular the incidence and the end effect of nocturnal respiratory obstruction (NRO). All PPFs over a 17-year period performed at one institution and by the same surgeon were examined retrospectively. All medical records from the Commission of Handicapped Children of patients who had a PPF were reviewed. Patients with NRO were identified clinically, and sleep studies were administered with two or more of the clinical triad. During a 17-year period, 111 patients underwent a PPF to treat velopharyngeal incompetence. Twelve patients were identified with a syndromic association in addition to a clefting disorder, of which most (N = 9) consisted of Pierre Robin syndrome. The median age at PPF performance was 6.0 years and the average follow-up was 7.4 years. The early postoperative complication rate was 10%, including a 7.2% incidence of respiratory obstruction and 0.9% postoperative bleeding. Twenty-one patients (19%) had late complications or unsatisfactory results. Twelve patients (10.5%) developed NRO, and patients with Pierre Robin syndrome were particularly prone-4 of 9 patients developed this complication. Nine of 12 patients with NRO had sleep studies performed with a minimum interval of 6 months postoperatively. Eight of the nine studies were normal. Of the NRO group, 3 patients had takedown of their PPF, including the patient with an abnormal sleep study. All 3 patients improved markedly and none developed recurrence of velopharyngeal insufficiency. NRO is not an uncommon finding in PPF patients, but NRO does not necessarily imply the presence of obstructive sleep apnea. The consequences of persistent NRO over the long term deserve further study.

Airway Obstruction↗
PubMed1999

A method to improve the estimation of conduction velocity distributions over a short segment of nerve.

Accurate, noninvasive determination of the distribution of conduction velocities (DCV) among fibers of a peripheral nerve has the potential to improve both clinical diagnoses of pathology and longitudinal studies of the progress of disease or the efficacy of treatments. Current techniques rely on long distances of propagation to increase the amount of temporal dispersion in the compound signals and reduce the relative effect of errors in the forward model. The method described in this paper attempts to reduce errors in DCV estimation through transfer function normalization and, thereby, eliminate the need for long segments of nerve. Compound action potential (CAP) signals are recorded from several, equally spaced electrodes in an array spanning only a 10-cm length of nerve. Relative nerve-to-electrode transfer functions (NETF's) between the nerve and each of the array electrodes are estimated by comparing discrete Fourier transforms of the array signals. NETF's are normalized along the array so that waveform differences can be attributed to the effects of temporal dispersion between recordings, and more accurate DCV estimates can be calculated from the short nerve segment. The method is tested using simulated and real CAP data. DCV estimates are improved for simulated signals. The normalization procedure results in DCV's that qualitatively match those from the literature when used on actual CAP recordings.

Action Potentials↗
PubMed1998

Two lyophilized polymer matrix recombinant human bone morphogenetic protein-2 carriers in rabbit calvarial defects.

We have developed a lyophilized bone morphogenetic protein (BMP) delivery device that can be formulated to control release over 2 to 8 weeks. Bioerodible poly (d,l lactide-co-glycolide) particles loaded with 90 micrograms recombinant human BMP-2 were suspended in either carboxymethylcellulose (CMC) or methylcellulose (MC) implants. Plain CMC and MC implants served as controls, as did a nonimplanted group. A total of 40 rabbits was evaluated histologically 2, 4, or 8 weeks after receiving circular full-thickness 15-mm calvarial defects. MC appeared to prevent prolapse of periosteum and dura into the defects and did not elicit bone growth. Addition of BMP improved the result. CMC implants appeared to encourage bone growth even in the absence of BMP. When BMP was added, new bone formed earlier. CMC may influence new bone formation because it is hydrophilic. MC is less hydrophilic and may cause undue inflammation. Either can be combined with BMP to produce unitary devices that are easy to make and use.

Animals↗
PubMed1997

Endoscopic retrieval of severed flexor tendons: a study of technique using cadaveric hands.

Retrieval of retracted zone 1, 2, and 3 flexor tendons without a proximal incision can occasionally lead to excessive tendon trauma or injury to neurovascular structures. To determine if endoscopic flexor tendon retrieval is a reliable, reproducible technique, 34 zone 2 flexor tendon lacerations were created in four cadaveric hands (2 male; 2 female). The tendons were retracted proximally an average of 4.3 +/- 1.9 cm (range, 2-10 cm) through a separate transverse wrist incision. A 2.5-mm flexible endoscope was introduced into the distal tendon sheath, and all transected tendons (N = 34) were clearly visualized. Thirty-two tendons (94%) were retrieved endoscopically by using either a loop snare or grasping forceps. Two tendons (6%) in a small female hand could not be retrieved endoscopically. This minimally invasive technique may be an alternative to the blind grasping maneuvers, proximal incision extensions, and counter-incisions in the palm.

Cadaver↗
PubMed1996

Lower extremity free flaps: a review.

OBJECTIVE: To identify factors related to free-flap coverage of lower extremity fractures that are linked to a negative outcome. DESIGN: A chart review. SETTING: A large microsurgical referral centre. PATIENTS: From 1981 to 1989, the records of all patients who underwent free-tissue transfer to the lower extremity with more than 1 year of follow-up were selected. From this was drawn a subgroup of 49 patients (mean age, 36 years) who had tibial fractures (55% were motor vehicle injuries) and in almost all cases established soft-tissue or bony defects. They formed the study group. INTERVENTION: Free-flap transfer. OUTCOME MEASURES: Factors that might be associated with free-flap failure: mechanism of injury, grade of tibial fracture, history of smoking, diabetes, peripheral vascular disease, ischemic heart disease, vascular compromise in the leg preoperatively, recipient artery used, type of anastomosis, and hypertension or hypotension intraoperatively. RESULTS: Type IIIB tibial fractures were the most frequent (67%) and carried a significantly (p = 0.02) higher risk of free-flap failure than other types of fracture. Patients underwent a mean of four procedures before referral for free-tissue transfer. The mean time from injury to flap coverage was 1006 days. Stable, long-term coverage of the free flaps was achieved in 78% of patients. Wound breakdown was most often caused by recurrent osteomyelitis (65%). Seventy-four percent of the fractures healed. The amputation rate was 10%. Four patients required repeat free-flap transfer for limb salvage. CONCLUSIONS: Only the grade of tibial fracture could be significantly related to postoperative free-flap failure.

Adolescent↗
PubMed1996

Bone anchors: new application in craniofacial surgery.

Postoperative ptosis of the soft tissues of the face after subperiosteal exposure of midfacial fractures may result in loss of zygomatic projection due to malposition of the soft-tissue envelope with respect to the underlying skeleton. Resuspension of the soft tissues of the face to their preinjury position has previously been suggested to alleviate this problem. We present a modification of our original technique, which uses suture anchors to simplify this procedure.

Adult↗
PubMed1995

A new method of skin-graft stabilization: the Reston technique.

We describe a new staple-on dressing technique for skin-graft stabilization, using gas-sterilized polyurethane foam as bolster material. The method has all the attributes of a satisfactory skin-graft dressing: compression to prevent hematoma and seroma, resistance to shear forces, splinting properties, and protection from the outside environment. Although we have not completed a randomized, prospective study, skin-graft "take" appears to be excellent in most cases. The technique is cost effective, and application requires a fraction of the time required for a traditional bolster dressing.

Buttocks↗
PubMed1995

Reconstruction of midfacial defects after surgical resection of malignancies.

Midfacial and orbital defects after ablative oncologic surgery are difficult problems for the reconstructive surgeon. Our goal is to address the devastating functional and aesthetic consequences of these extirpations and to improve the quality of life for this unfortunate group of patients. Partial maxillectomy defects are best treated by skin grafting the residual cavity and reconstructing the maxillary defect by prosthetic means. Local tissues can be used when the defects are small and the bone loss is not extensive. For massive midfacial defects with insufficient bony support for prosthetic reconstruction, osseocutaneous free flaps have proved useful to restore contour and the necessary structural support.

Face↗
PubMed1995

Intraoral reconstructive techniques.

A multitude of reconstructive options are possible for the patient afflicted with an intraoral malignancy. The reconstructive technique chosen depends on the stage of the disease and the extent of the soft- and hard-tissue defects after extirpation. A graded approach is applied to reconstruction. If local tissues are not available for reconstruction, the surgeon must look to more distant sites in choosing a reconstructive procedure. Microsurgical transfer of composite tissues have allowed us a high degree of success in effecting immediate one-stage closure of complex three-dimensional wounds.

Carcinoma, Squamous Cell↗
PubMed1995

The ramifications of immediate reconstruction in the management of breast cancer.

A retrospective review of 50 patients who underwent immediate postmastectomy breast reconstruction was performed to determine the effect of reconstruction on the treatment of these patients. The overall complication rate was 50% (25 of 50). Smoking statistically correlated with an increased rate of wound complications (0 = 0.0001). Obese patients had nearly twice as many wound complications; however, this finding was not statistically significant (P = 0.261). Eleven of the 50 patients underwent reconstruction with a prosthesis, with an overall complication rate of 64% (seven of 11) and a 55% (six of 11) rate of prosthesis loss. Thirty-nine of the 50 patients underwent reconstruction with autologous tissue. Forty-six per cent (18 of 39) of the patients in the autologous group developed complications, and eight required emergent reoperation to prevent flap loss. The wound complication rate was significantly lower for bipedicled transverse rectus abdominis muscle (TRAM) flap reconstructions than for other forms of autologous reconstruction (P = 0.040). total operative time (including mastectomy) was 3.11 hours (range, 2-4 hours) for the prosthetic group and 9.4 hours (range, 5-15 hours) for the autologous group. All but two patients undergoing autologous tissue reconstruction required blood transfusions; an average of 2.4 U of blood was transfused per patient (range, 0-7 U). Only two patients in the prosthetic group required a transfusion. The average hospital stay was 5 days (range, 2-7 days) for the prosthetic group and 8.3 days (range, 5-19 days) for the autologous tissue group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Assessing medical students' and surgery residents' clinical competence in problem solving in surgical oncology.

BACKGROUND: We sought to determine the competence of medical students and surgery residents in evaluating clinical problems (using both real and simulated patients) in surgical oncology. METHODS: Forty-five third-year medical students, 23 first postgraduate year (PGY-1) residents, and seven second postgraduate year (PGY-2) residents were presented with the same four clinical problems (breast evaluation, prostate nodule, colon cancer, and mole evaluation). The two resident groups were presented with two additional patients (breast cancer options and thyroid mass). RESULTS: Mean performance scores for the problems were generally poor (32-72%); most students and residents failed almost all of the problems. Level of training was of some importance; the overall mean scores of the PGY-2 residents were superior to those of the medical students and the PGY-1 residents (p = 0.049). However, in many areas of information gathering, diagnosis, and management, training level appeared to have no impact. Numerous important performance deficits were identified in all groups. CONCLUSION: Medical students and surgery residents are not receiving adequate training in diagnosing and treating important problems in surgical oncology.

Analysis of Variance↗
PubMed1994

An assessment of postnatal growth after in utero long bone osteotomy with fixation.

Researchers have recently suggested that rigid fixation of the immature bony skeleton may restrict growth and development. This study assesses the effect on postnatal growth of an in utero tibial osteotomy fixed with a miniplate in fetal sheep. A midshaft osteotomy was performed on fetal sheep tibia (n = 5) at 95 days' gestation (term 145 days). One tibia was reduced and fixed with a titanium miniplate and screws, while the contralateral hindlimb served as a control. The newborns were vaginally delivered and sacrificed at 2 months of age. The hindlimbs, control and fractured, were harvested, stripped of soft tissue, and the tibia, femur, and distal metatarsal were each measured and weighed. Each tibia also underwent radiographic analysis and histologic examination (after decalcification) using hematoxylin and eosin, Sirius red, and Alcian blue stains. No prenatal, postnatal, or perioperative medical complications occurred. Apart from a slight angulation in one operated tibia, no gross morphologic differences, either visible or palpable, were found between the operated and control limbs. This was confirmed radiographically where no remnant of the osteotomy site was visible. Measurements of the operated and control tibias, femurs, and metatarsal bones were not statistically different. Histologic analysis showed a total incorporation of bone at the osteotomy site with appositional growth present. All bone was lamellar with longitudinal orientation. In the area of the screw sites, the surrounding bone shaft was the same width as its neighboring bone.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Sequentially linked free flaps in head and neck reconstruction.

Free tissue transfer has become a useful technique for reconstructing complex three-dimensional defects following the extirpation of head and neck malignancies. This technique, however, may be limited by inadequate vascularity in the recipient site when a patient has been subjected to operative procedures or radiation therapy. The use of serial flaps, with the first flap connected sequentially to the second, reduces the need for dual recipient vessels in a surgical field when two flaps are required for reconstruction. Although this procedure is more technically demanding than more traditional approaches, it can provide a satisfactory, reliable one-stage composite reconstruction under these difficult circumstances. Results have been functionally and aesthetically superior to those achieved with pedicled one-flap reconstructive methods.

Carcinoma, Squamous Cell↗
PubMed1993

The medical leech: an old treatment revisited.

The treatment modality of choice for venous insufficiency after free tissue transfer or replantation remains surgical repair. When this is not technically possible, the use of medical leeches is a useful adjunct to treatment. This paper reviews the history of the use of leeches in medicine, the anatomy and physiology of Hirudo medicinalis, the techniques of leech therapy, and the complications and contraindications.

Adult↗