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Biomedical subjects

Samir Mardini

Publications and source records attributed to Samir Mardini.

At least 37 records · Page 2Linked to original sources
PubMed2005

A model for chronic osteomyelitis using Staphylococcus aureus in goats.

Animal models of osteomyelitis traditionally have been characterized by inherent weaknesses related to animal size, differences in clinical findings compared with humans, aggressive behavior, high complication rate, and high cost. In this experiment, a model of tibial osteomyelitis was established in 28 goats with a very low complication rate and a consistent clinical, radiographic, and histologic disease course. The infecting Staphylococcus aureus organism was isolated in all but five of 28 animals (82%), in which there was no growth of bacteria at 24 and 72 hours. All five of these specimens had histologic evidence of osteomyelitis. Twenty-seven of the 28 animals (96%) had radiographic and histologic evidence of osteomyelitis. Clinical progression of the disease was observed by draining wounds, a postoperative limp that subsided in all goats, and varied periods of anorexia despite an average increase in body weight. There were no complications or mortalities related to the establishment of the animal model. This large animal model will provide a practical method of studying osteomyelitis and comparing treatment protocols.

Animals↗
PubMed2005

Surgical strategy for infant obstetrical brachial plexus palsy: experiences at Chang Gung Memorial Hospital.

BACKGROUND: Strategies for management of infant obstetrical brachial plexus palsy remain controversial, including timing of surgery and treatment modalities. METHODS: The senior author (Chuang) performed surgical explorations on 78 infant obstetrical brachial plexus palsy patients from 1992 to 1999. Sixty-eight patients underwent brachial plexus operation during the infant period (2 to 11 months), and 10 patients underwent surgery beyond the infant period. RESULTS: For the ruptured upper and/or middle trunk injury (Erb's palsy), better shoulder and elbow function was observed in those who received numerous short grafts from C5 to the suprascapular and posterior division and from the C6 spinal nerve to the anterior division of the upper trunk. For the rupture injury associated with root avulsion (total palsy), nerve graft and transfer (intraplexus and extraplexus) provided a one-stage reconstruction for shoulder, elbow, and especially hand functions. The contralateral C7 or ipsilateral part of the ulnar nerve transfer was rarely used in infant obstetrical brachial plexus palsy, compared with adult brachial plexus injury. CONCLUSIONS: The operative results proved that earlier timing of nerve surgery (within 3 months) is strongly indicated in patients who have total palsy, and only relatively indicated in patients with isolated rupture of the upper plexus.

Birth Injuries↗
PubMed2005

Volumetric change of the muscles of mastication following resection of mandibular angles: a long-term follow-up.

Mandibular angle resection is an accepted procedure for the correction of square face appearance due to mandibular angle prominence. Long-term follow-up of the changes in volume that occurs in the muscles of mastication and osseous structures has been inadequate in the literature. In this study, 3-dimensional computed tomography data were used to extract the mandible, masseter, medial pterygoid, and lateral pterygoid muscles for assessment of the volumetric changes that took place after angle reduction in 7 patients (14 hemimandibles) with an average age of 24.9 years and a mean follow-up time of 4.5 years. All measurements were performed twice to assure accuracy, with a difference of 1.2 +/- 1.1% noted. The hemimandible volume was reduced by 12.6% immediately after the reduction procedure and 8.2% at final follow-up. Osseous regeneration was observed as thickening of the bone and partial regrowth of the angles. None of the 14 hemimandibles had a complete return of the preoperative angular shape. The volumetric changes that occurred in the muscles of mastication were inconsistent among the patients. The masseter muscle was reduced by 5.2%, the medial pterygoid muscle was reduced by 14.4%, and the lateral pterygoid muscle was increased by 5.7% at final follow-up. The medial pterygoid muscle change was more significant than that of the masseter muscle (P = 0.00361). The objective findings of this study were not in agreement with the conventional thought and clinical impression that the masseter muscle becomes atrophic after mandibular angle resection. Only a slight reduction occurred in some patients in the volume of the muscles, with some actually displaying a slight increase. The end result was a satisfactory esthetic outcome for the patients in the long term despite the minor changes in muscle volume and slight bony regeneration that occurred.

Adolescent↗
PubMed2005

Intussusception of a transferred jejunal flap in cervical esophagus reconstruction.

Although jejunal flaps have been used frequently for esophageal reconstruction, and the techniques for transfer, as well as subsequent modification, have been well described, a variety of complications still poses problems for both physicians and patients. The challenge exists in avoidance and management of complications. The purpose of this report is to present an unusual but severe complication involving a jejunal flap that was transferred to the neck for esophageal reconstruction. Intussusception of the jejunal flap occurred 1 year after flap transfer due to redundancy of the transferred segment. The patient was a child who had esophageal reconstruction for severe dysphagia that was due to a previous history of radiation injury. The disorder was successfully treated surgically with manual reduction of the intussuscepted segment, followed by shortening of the jejunal flap to prevent future recurrence. One should keep in mind that redundancy of the reconstructed esophagus may cause dysphagia due to kinking or, in this case, intussusception, which may result in necrosis of a segment of the transferred jejunum. One of the measures that should be taken during the initial reconstruction to prevent these serious complications is to perform the final inset of the jejunal flap after revascularization. This allows for proper assessment of jejunal length, which undergoes a significant change after restoration of the vascular supply.

Child↗
PubMed2005

Tubed deltopectoral flap for creation of a controlled esophagocutaneous fistula in patients with persistent choking following esophageal reconstruction with free diversionary jejunum.

Esophageal reconstruction in patients with abnormal pharyngeal muscles or epiglottis may result in episodes of choking. The jejunal flap has been used to prevent choking by insetting the proximal end into the gingivobuccal sulcus and separating the digestive tract from the airway. A technique has been developed to deal with patients with aspiration due to collection of food near the nonfunctioning epiglottis. Between 1997 and 2004, 25 patients underwent reconstruction with jejunal flaps inset into the gingivobuccal sulcus. Postoperatively, 5 patients presented with episodes of choking. All patients underwent creation of an esophagocutaneous fistula using a deltopectoral flap. All flaps survived. Choking resolved and vocal performance was preserved in all patients. The jejunum, inset proximally into the gingivobuccal sulcus, has been successful in reconstructing patients unable to separate the airway from the digestive tract. The deltopectoral flap provides tissue for creation of a tubed flap and allows for the creation of a long fistula that prevents aspiration and can divert oral fluids away from a tracheostomy or a fresh wound.

Airway Obstruction↗
PubMed2005

Intracranial space, brain, and cerebrospinal fluid volume measurements obtained with the aid of three-dimensional computerized tomography in patients with and without Crouzon syndrome.

OBJECT: The authors attempt to provide a standard for volumes of the intracranial space, brain, and cerebrospinal fluid (CSF) in healthy control individuals by using in vivo three-dimensional (3D) computerized tomography (CT) data and to compare these data with those obtained from a group with Crouzon syndrome. METHODS: Fifty-seven individuals underwent 3D head CT scanning for nonintracranial-related disease to produce a set of normal volumes for the intracranial space, brain, and CSF. Prediction limits of 95% were obtained to provide a range of acceptable volumes throughout the growing period and early adulthood. Eleven patients (seven boys and four girls, age range 2.2 months-13.4 years) with Crouzon syndrome underwent identical measurements, which were compared with those of the control patients. The control group comprised 35 boys and 22 girls who ranged in age from 0.26 months to 24.4 years. Intracranial space and brain volume showed a progressive increase with age, with three different slopes from birth to adulthood. Male patients were found to have larger volumes than female patients in the same age group. Volume patterns for CSF were not significantly different within a given age or sex. Six patients with Crouzon syndrome had intracranial and brain volumes within the 95% prediction limit, three patients measured above the limit, and two measured below. CONCLUSIONS: A standard for volumes of intracranial space and structures provides a guideline for the evaluation of patients with intracranial disease. Volumes in patients with Crouzon syndrome can be matched to their normal age- and sex-matched counterparts.

Adolescent↗
PubMed2004

Free-style free flaps.

Free-tissue transfer has become the accepted standard for reconstruction of complex defects. With the growth of this field, anatomic studies and clinical work have added many flaps to the armamentarium of the microvascular surgeon. Further advancements and experience with techniques of perforator flap surgery have allowed for the harvest of flaps in a free-style manner, where a flap is harvested based only on the preoperative knowledge of Doppler signals present in a specific region. Between June of 2002 and September of 2003, 13 free-style free flaps were harvested from the region of the thigh. All patients presented with an oral or pharyngeal cancer and underwent resection and immediate reconstruction of these flaps. All flaps were cutaneous and were harvested in a suprafascial plane. The average size of the flaps was 108 cm2 (range, 36 to 187 cm2), and the average length of the vascular pedicle was 10 cm (range, 9 to 12 cm). All flaps were successful in achieving wound coverage and functional outcomes without any vascular compromise necessitating re-exploration. Free-style free flaps have become a clinical reality. The concepts and techniques used to harvest a free-style free flap will aid in dealing with anatomic variations that are encountered during conventional flap harvest. Future trends in flap selection will focus mainly on choosing tissue with appropriate texture, thickness, and pliability to match requirements at the recipient site while minimizing donor-site morbidity.

Adult↗
PubMed2004

Cranial repair using BMP-2 gene engineered bone marrow stromal cells.

BACKGROUND: Bone grafts, allografts, and biocompatible artificial bone substitutes all have their shortcomings when used for the repair of cranial bone defects. Tissue engineered bone shows promise as an alternative for the repair of these defects. MATERIALS AND METHODS: Rabbit bone marrow mesenchymal stromal cells (MSCs) were separated from iliac crest aspirates and expanded in a monolayer culture 1 month before implantation. These MSCs were then infected with replication-defective adenovirus-human BMP-2 genes 1 week before implantation. Bilateral critical-size cranial defects were created in the animal with removal of osteoinductive periosteum and dura. MSCs were mixed with alginate UP (ultrapure) to form MSC/polymer construct. MSCs used for the control site were infected with adenovirus beta-galactosidase (beta-gal). After 1 week, 6 weeks, and 3 months, five rabbits from each experimental group were sacrificed and the cranial defect site was examined by histology study. RESULTS: Near-complete repair of the large size cranial defects using the tissue engineered MSC/alginate construct was observed. The H&E stain and von Kossa's staining should better regenerate bone at the experiment site. A statistically significant difference in bone formation was noted by 3D CT imaging at 3 months post-BMP-2 treatment of the cranial defects (0.79 +/- 0.06 versus 0.47 +/- 0.05 cm(2), P < 0.001) but not at 6 weeks (0.36 +/- 0.04 versus 0.33 +/- 0.03 cm(2), P = 0.347). CONCLUSIONS: Near-complete repair of large cranial defects can be achieved using tissue engineered bone. The use of newly developed polymers as well as the integration of the stem cell concept with gene medicine is necessary to attain this goal.

Adenoviridae↗
PubMed2004

Reconstruction of the hand and upper limb with free flaps based on musculocutaneous perforators.

Since the advent of perforator flaps, a wide variety of applications have been documented. This study focuses on free flaps based on musculocutaneous perforators, because they have not been well-described in the literature of upper-limb reconstruction. They can be trimmed to be thin and pliable, and may provide large flaps with multiple components on the same pedicle to facilitate three-dimensional inset of flaps. Microvascular free flaps based on musculocutaneous perforators were performed in 36 cases for reconstruction of the thumb and thenar web, palm, dorsum of the hand, wrist, and forearm. They included the anterolateral thigh perforator flap (27 cases), thoracodorsal perforator flap (5 cases), and deep inferior epigastric perforator flap (4 cases). In 2 other cases not included in this series, the thoracodorsal perforator flap could not be elevated due to anatomical variations. There was no failure in this series, but complications included: 1) hematoma in 2 cases, and 2) infection in 2 cases with flap rim necrosis which was treated by a local rotation flap and skin graft. The thin flaps facilitated secondary reconstructive procedures, and only minor effort was required for the debulking procedure of the flaps. On average, these patients required 2.3 occasions of secondary procedures for further reconstruction following coverage with a perforator flap. The perforator flaps provide medium-thickness flaps for coverage of large defects in the upper limb with improved aesthetics and function. With careful dissection of the musculocutaneous perforators and primary thinning of the flaps, the use of a perforator flap is quite safe. Preservation of the muscles leads to better preservation of donor-site functions. Less requirement of secondary debulking procedures is a great advantage. However, caution should be taken in the presence of wound infection.

Adolescent↗
PubMed2004

Double free flaps harvested from one or two donor sites for one or two-staged burn reconstruction: models of sequential-link and independent-link microanastomoses.

Extensive burn injuries and subsequent scarring result in functional and aesthetic impairments. The use of free flaps in burn reconstructions provides superior outcomes especially when other, more conservative reconstructive methods fail and curtail efforts of relentless rehabilitation. Multiple chronic scar-associated problems and extensive acute burn defects are conventionally resolved by multiple procedures. Thus, two or extensive scar regions are typically reconstructed using two free flaps (double free flaps) in two separate, procedures utilizing two independent donor sites. This leads to a protracted course of repetitive operations, hospitalizations, and rehabilitation, causing a prolonged period of discomfort and disability. The definition of double free flaps is two independent free flaps with two sets of microanastomoses. This paper illustrates, via a case-series, that double free flaps could be performed in one procedure, with both flaps harvested from either one or two donor sites. Two flaps are then utilized to resolve one large or two problem areas at the same time. Revascularization of the flaps is achieved via either a sequential-link or independent-link microanastomoses. The advantages of harvesting double free flaps from one region and using them in one stage to reconstruct one or two defect area include: (1) providing a large area of soft, pliable skin from one region for re-surfacing burn injuries or resolving scar associated problems, (2) decreasing the treatment course and potential disability, (3) decreasing donor site morbidities, (4) increasing maneuverability and conformability of the flap, and (5) affording a better functional and aesthetic outcome.

Adult↗
PubMed2004

Extended trapezius myocutaneous free flap for the reconstruction of a foot defect lacking adjacent recipient vessels.

Foot reconstruction requires tissue that is durable and can withstand the extremes of pressure and stress. The trapezius myocutaneous flap has not been used previously as a free flap for foot reconstruction. In this report, the trapezius was used as an extended myocutaneous free flap for the reconstruction of a foot wound lacking adjacent and adequate recipient vessels. The extended trapezius flap may be one of the longest free flaps that can be harvested. The indications for the use of this flap are limited. In an extremity that lacks adequate recipient vessels adjacent to the defect, this flap can be extended such that more proximal vessels in the leg can be used as the recipient vessels without the need for vein grafts to bridge the distance. The donor-site morbidity of this flap is minimal when the superior fibers of the trapezius muscle and its innervation are preserved.

Accidents, Traffic↗
PubMed2004

Free proximal gracilis muscle and its skin paddle compound flap transplantation for complex facial paralysis.

Gracilis functioning free-muscle transplantation for the correction of pure facial paralysis has been a preferred method used by many reconstructive microsurgeons. However, for complex facial paralysis, the deficits include facial paralysis along with soft-tissue, mucosa, and/or skin defects. No adequate solution has been proposed. Treatment requests in those patients are not only for facial reanimation but also for correction of the defects. Of 161 patients with facial paralysis treated with gracilis functioning free-muscle transplantation from 1986 to 2002, eight patients (5 percent) presented with complex deficits requiring not only facial reanimation but also aesthetic correction of tissue defects. The tissue defects included an intraoral defect created following contracture release (one patient), infra-auricular radiation dermatitis with contour depression (one patient), temporal depression following a temporalis muscle-fascia transfer (one patient), ear deformity (two patients), and infra-auricular atrophic tissue with contour depression (three patients). A compound flap, consisting of a gracilis muscle with its overlying skin paddle separated into two components, was transferred for simultaneous correction of both problems. The blood supply to the gracilis and to the skin paddle originated from the same source vessel and therefore required the anastomosis of only one set of vessels. The versatility of this compound flap allows for a wide arc of rotation of the skin paddle around the muscle. All flaps were transferred successfully without complications. Satisfactory results of facial reanimation were recorded in five patients after all stages were completed. The remaining three patients are undergoing physical therapy and waiting for revision of the skin paddle.

Adolescent↗
PubMed2004

Free split-cutaneous perforator flaps procured using a three-dimensional harvest technique for the reconstruction of postburn contracture defects.

With recent advances in free-tissue transfer, microsurgical techniques have been used more frequently for the reconstruction of postburn contracture defects. Traditional methods, including full-thickness skin grafts and local flaps, often result in a good outcome; however, multiple operative procedures, long periods of splinting, and physical rehabilitation are often required. Free split-cutaneous perforator flaps, consisting of one large cutaneous paddle with two perforating vessels split into two separate skin regions, were used for two kinds of postburn contractures: rectangular and spatially separate defects. From September of 2000 to October of 2002, seven patients underwent this method of reconstruction at Chang Gung Memorial Hospital in Taiwan. A three-dimensional flap harvest method, in which the skin paddle is circumferentially elevated early in the harvest, was used. Postburn scar contractures had resulted from flame burns in six cases and an electric burn in one case. The reconstructive regions included the neck in two patients, the breast in one patient, and the hand in four patients. There were six male patients and one female patient, with a mean age of 34.8 years (range, 25 to 49 years). The size of the excised scar ranged from 120 cm2 to 308 cm2 (mean, 162.3 cm2). The size of the unsplit flaps ranged from 144 cm2 to 337.5 cm2 (mean, 192.1 cm2). The average time for flap harvest using this three-dimensional harvest technique was 39.1 minutes. The average total operative time was 4.3 hours. The average total hospital stay was 7.3 days (range, 6 to 11 days). All flaps survived without major complications. The donor site was closed primarily in all cases. At a mean follow-up time of 9 months, the functional and aesthetic outcomes showed significant improvement as compared with the preoperative condition. In this study, a new method of flap harvest using a three-dimensional technique is introduced, and its application in the reconstruction of postburn contractures is evaluated.

Adult↗
PubMed2004

Periareolar approach for the correction of congenital symmastia.

This report elucidates the continued and relatively rare problem of congenital symmastia and its surgical repair without concomitant bilateral breast reduction. This case highlights the use of suction-assisted lipectomy techniques to address the excess fat in the presternal web and a periareolar approach for access to the intermammary space. The periareolar incision allows for the use of a concealed approach and the avoidance of a central scar that could result in hypertrophy or keloid formation, especially in this patient who is more prone to hypertrophic scarring. Furthermore, plication of the central web dermis to the sternal periosteum in a more superior position serves to not only correct the symmastia but also redrape the excess skin and restore the blunted inframammary folds.

Adult↗
PubMed2004

Bowel preparation before microvascular free colon transfer for head and neck reconstruction: is it necessary?

Mechanical bowel preparation before any intestinal operation, especially when the large intestine is involved, is routine practice for most surgeons. This practice has been questioned by many colorectal surgeons, with convincing data showing the lack of benefit of preoperative mechanical bowel preparation. Free microvascular transfer of the large intestine is occasionally performed for reconstruction of the upper esophagus, as it provides a better size match for the oropharynx than other visceral organs. Nine patients underwent reconstruction of the cervical esophagus and voice tube using a segment of ileocolon. In all patients, the cervical esophagus was reconstructed using the ascending colon and the voice tube was reconstructed using the ileal segment. Both were transferred as one free flap. All patients underwent the procedure without any form of preoperative mechanical bowel preparation. The patients were able to tolerate a solid diet at the end of the mean follow-up period of 7 months, and all esophagograms showed no evidence of stricture formation. One patient developed a fistula at the recipient site that was treated with a regional flap, one patient developed a superficial wound infection of the abdominal wall, and one patient developed a postoperative abdominal wound dehiscence after several episodes of excessive coughing. Microvascular transfer of a large intestinal segment without preoperative mechanical bowel preparation for the reconstruction of the esophagus is a safe procedure. It can avoid the discomfort and complications associated with mechanical bowel preparation. If preoperative mechanical bowel preparation is preferred, the results of this study, which are based on nine patients, demonstrate the safety of this practice in cases where the patient did not follow proper instructions or in cases where the use of the colon was not anticipated preoperatively.

Aged↗