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Biomedical subjects

E Santamaria

Publications and source records attributed to E Santamaria.

At least 19 recordsLinked to original sources
PubMed2000

Kinetic characterization of Desulfovibrio gigas hydrogenase upon selective chemical modification of amino acid groups as a tool for structure-function relationships.

The effect of amino acid residues modification of Desulfovibrio gigas hydrogenase on different activity assays is reported. The first method consisted in the modification of glutamic and aspartic acid residues of the enzyme with ethylenediamine in order to change the polarity of certain regions of the protein surface. The second method consisted in the modification of histidine residues with a Ru complex in order to change the acid-base properties of the histidine residues. The implication of these modifications in the enzyme kinetics has been studied by measuring in parallel the activities of para/ortho hydrogen conversion, deuterium/hydrogen exchange and dyes reduction with hydrogen. Our experimental data support some hypothesis based on the three-dimensional structure of this enzyme: (a) electrostactic interactions between the hydrogenase and the redox partner play an essential role in the kinetics; (b) the histidine ligand and the surrounding acidic residues of the distal [4Fe4S] cluster form the recognition site of the redox partner of the hydrogenase; and (c) histidine residues are involved in the hydron transfer pathway of the hydrogenase.

Amino Acids↗
PubMed2000

Radial forearm free tissue transfer for head and neck reconstruction: versatility and reliability of a single donor site.

Since its description as a free flap, the radial forearm flap has undergone numerous modifications for reconstruction of various defects in the head and neck region. Fasciocutaneous, adipofascial, osteocutaneous, tendinofasciocutaneous, or osteotendinofasciocutaneous flaps may be designed and transferred from the radial forearm. This article illustrates the versatility and reliability of this donor site in 15 patients with a variety of head and neck oncologic defects who underwent immediate (12 patients) and delayed (3 patients) reconstruction using different free flaps from the radial forearm. Skin flaps were used in 11 patients (73.3%) with floor of mouth (4 cases), hemiglossectomy (2 cases) and partial maxillectomy (2 cases) defects, and for scalp (1 case), lower lip (1 case) and a central face (anterior maxilla/upper lip/nasal) (1 case) defect. Osteocutaneous flaps were used in four patients (26.6%) for reconstruction of bilateral subtotal maxillectomy defects (2 cases), a complex forehead and nasal defect (1 case), and for mandible reconstruction (1 case). In addition, the palmaris longus tendon was included with the flap in the two patients that required oral sphincter reconstruction. One patient required reexploration due to vein thrombosis, and no flap failures were detected in this series. The donor site healed uneventfully in all patients, except one, who had partial skin graft failure. Because of their multiple advantages, free flaps from the radial forearm have a definite role for reconstruction of head and neck defects. New applications of composite flaps from this donor site may continue to emerge, as illustrated in some of our patients.

Adult↗
PubMed2000

Prevention of ischemia-reperfusion injury in a rat skin flap model: the role of mast cells, cromolyn sodium, and histamine receptor blockade.

The objective of this study was to examine the role of mast cells and their principal product, histamine, in ischemia/reperfusion injury. Cromolyn sodium, diphenhydramine, and cimetidine were administered to ischemic flaps just before reperfusion and evaluated for flap survival, mast cell count, neutrophil count, and myeloperoxidase levels. Epigastric island skin flaps were elevated in 49 rats; they were rendered ischemic by clamping the artery for 10 hours. Thirty minutes before reperfusion, the rats were treated with intraperitoneal saline (n = 11), cimetidine (n = 11), diphenhydramine (n = 11), or cromolyn sodium (n = 10). Flap survival was evaluated at 7 days. Neutrophil counts, mast cell counts, and myeloperoxidase levels were evaluated 12 hours after reperfusion. Flap necrosis in the sham group of animals (n = 6) was 0.0 percent, as expected, whereas the control group (saline-treated animals) had 47.3+/-33.4 percent necrosis. Animals treated with diphenhydramine and cimetidine demonstrated a significant decrease in flap necrosis to 17.7+/-8.8 percent and 19.4+/-14.7 percent, respectively. This protective effect was not seen with cromolyn sodium (44.3+/-35.6 percent). Both neutrophil and mast cell counts were significantly decreased in flaps from antihistamine-treated and sham animals versus both saline- and cromolyn sodium-treated groups. The administration of diphenhydramine and cimetidine before reperfusion can significantly reduce the extent of flap necrosis and the neutrophil and mast cell counts caused by ischemia/reperfusion. This protective effect is not seen with cromolyn sodium. The protective effect of antihistamines on flap necrosis might be related to the decrease in neutrophils and, possibly, mast cells within the flap.

Animals↗
PubMed2000

A classification system and algorithm for reconstruction of maxillectomy and midfacial defects.

Maxillectomy defects become more complex when critical structures such as the orbit, globe, and cranial base are resected, and reconstruction with distant tissues becomes essential. This study reviews all maxillectomy defects reconstructed immediately using pedicled and free flaps to establish (1) a classification system and (2) an algorithm for reconstruction of these complex problems. Over a 5-year period, 60 flaps were used to reconstruct defects classified as the following: type I, limited maxillectomy (n = 7); type II, subtotal maxillectomy (n = 10); type IIIa, total maxillectomy with preservation of the orbital contents (n = 13); type IIIb, total maxillectomy with orbital exenteration (n = 18); and type IV, orbitomaxillectomy (n = 10). Free flaps (45 rectus abdominis and 10 radial forearm) were used in 55 patients (91.7 percent), and the temporalis muscle was transposed in five elderly patients who were not free-flap candidates. Vascularized (radial forearm osteocutaneous) bone flaps were used in four of the 60 patients (6.7 percent) and nonvascularized bone grafts in 17 (28.3 percent). Simultaneous reconstruction of the oral commissure using an Estandler procedure was performed in 10 patients with maxillectomy and through-and-through soft-tissue defects. Free-flap survival was 100 percent, with reexploration in five of 55 patients (9.1 percent) and partial-flap necrosis in one patient. Seven of the 60 patients (11.7 percent) had systemic complications, and four died within 30 days of hospitalization. Fifty patients had more than 6 months of follow-up with a mean time of 27.7 (+/- 15.6) months. Postoperative radiotherapy was administered in 32 of these patients (64.0 percent). Chewing and speech functions were assessed in 36 patients with type II, IIIa, and IIIb defects. A prosthetic denture was fixed in 15 of 36 patients (41.7 percent). Return to an unrestricted diet was seen in 16 patients (44.4 percent), a soft diet in 17 (47.2 percent), and a liquid diet in three (8.3 percent). Speech was assessed as normal in 14 of 36 patients (38.9 percent), near normal in 15 (41.7 percent), intelligible in six (16.7 percent), and unintelligible in one patient (2.8 percent). Globe and periorbital soft-tissue position was assessed in 14 patients with type I and IIIa defects. There were no cases of enophthalmos, and one patient had a mild vertical dystopia. Ectropion was observed in 10 of 14 patients (71.4 percent). Oral competence was considered good in all 10 patients with excision/reconstruction of the oral commissure; however, two patients (20 percent) developed microstomia after receiving radiotherapy. Aesthetic results were evaluated at least 6 months after reconstruction in 50 patients. They were good to excellent in 29 patients (58 percent) for whom cheek skin and lip were not resected, and poor to fair (42 percent) when the external skin or orbital contents were excised. Secondary procedures were required in 16 of 50 patients (32.0 percent). Free-tissue transfer provides the most effective and reliable form of immediate reconstruction for complex maxillectomy defects. The rectus abdominis and radial forearm flaps in combination with immediate bone grafting or as osteocutaneous flaps reliably provide the best aesthetic and functional results. An algorithm based on the type of maxillary resection can be followed to determine the best approach to reconstruction.

Algorithms↗
PubMed1999

Microvascular vastus lateralis muscle flap for chronic empyema associated with a large cavity.

Thoracic empyema can be disabling and may need microvascular free flaps in some intractable cases. After repeated failure of conventional thoracic surgical procedures, 2 patients with empyema were treated with microvascular free vastus lateralis muscle flaps for obliteration of the large empyema cavity. The reconstruction was successful in wound closure and eradication of infection. The donor site morbidity was minimal, and the patients resumed normal daily activities. Microvascular vastus lateralis muscle flap is the best option if free flaps are required for reconstruction of empyema.

Aged↗
PubMed1999

Factors associated with complications in microvascular reconstruction of head and neck defects.

The use of microvascular free tissue transfer has allowed the reconstruction of increasingly complex defects in higher risk patients after head and neck cancer resections. However, the combination of these factors also gives rise to a higher risk for the development of complications. This study was performed to establish the pretreatment factors associated with complication development after microvascular free tissue transfer for the reconstruction of defects resulting from head and neck cancer ablations, with particular attention to the role of comorbid conditions. A retrospective cohort study was conducted including 200 consecutive microvascular free tissue transfers performed for the reconstruction of surgical defects in the head and neck region at a single tertiary care institution. Comorbidity severity was assessed using the Charlson comorbidity index, a novel approach to comorbid staging in this setting. The flap survival rate was 98 percent. Complications developed in 56 cases (28 percent), with multiple complications occurring in 21 of these cases (10.5 percent). Univariate analysis revealed that prior radiation treatment (p = 0.03), anesthesia time over 10 hours (0.05), and advanced Charlson comorbidity grade (0.002) were associated with an increased risk for the development of complications. However, only the presence of advanced Charlson grade proved significant after multivariate analysis (odds ratio 3.9; 95 percent CI = 1.5 to 10.1). In addition, increasing Charlson grade (p = 0.003) and age over 70 years (p = 0.04) correlated with increasing complication severity. Systemic complications occurred in 28 patients (14 percent), with advanced Charlson grade being the only significant factor associated with the development of complications after controlling for confounding factors (odds ratio 3.8; 95 percent CI = 1.5 to 9.7). In patients over 70 years of age, increasing operative time also impacted on the development of systemic complications (p = 0.002), especially in patients with advanced Charlson grades (0.01). Recipient site complications occurred in 30 patients (15 percent), with history of prior radiation therapy being the only factor associated with increased risk by multivariate analysis (odds ratio 2.5; 95 percent CI = 1.1 to 5.7). No factors predicted the development of donor-site complications, which occurred in 11 cases (5.5 percent). The median hospital stay for the entire population was 16 days. The development of complications increased the median hospital stay by 7.5 days (p < 0.001). The effect of the development of complication on hospital stay remained significant even after controlling for the effects of confounding variables (relative risk = 9.87; 95 percent CI = 5.9 to 19.9). Microvascular surgery is a highly successful and relatively safe method for the reconstruction of large head and neck defects. The Charlson comorbidity index grading may be useful for identifying patients at increased risk for the development of complications after microvascular reconstruction, allowing for improved perioperative planning. In addition, patients with prior radiation exposure have a significantly higher risk for developing complications at the recipient site. Although advanced age is not associated with an increased risk for complications, older patients may be more sensitive to the effects of prolonged anesthesia and are likely to develop more severe complications.

Animals↗
PubMed1999

Sensation recovery on innervated radial forearm flap for hemiglossectomy reconstruction by using different recipient nerves.

The objectives of this study were (1) to determine the extent of sensory recovery on hemitongues reconstructed with innervated radial forearm flaps and (2) to assess the influence of various clinical and surgical factors over the return of sensation, including the use of different recipient nerves for neurorrhaphy. Twenty-eight patients with tongue cancer who underwent hemiglossectomy and primary reconstruction with innervated radial forearm flaps over a 3-year period were studied. Mean postoperative follow-up was 18.2 months (range 6 to 32 months). Sensory recovery was assessed in a blind manner by two examiners that used (1) static two-point discrimination, (2) light touch sensation, (3) pain perception, and (4) hot and cold temperature perception. Different surfaces were assessed with each method on the reconstructed hemitongue and on the intact contralateral hemitongue (used as control). The following factors and their relationship with flap sensory recovery were analyzed: age, smoking history, size of the reconstructed defect, administration of postoperative radiation therapy, recipient nerve, and neurorrhaphy technique. Comparative statistical analysis (p < 0.05) between both hemitongues was performed using paired t test followed by Bonferroni correction for static two-point discrimination and light touch sensation. Fisher exact test analysis was used for pinprick and hot and cold temperature perception. The control side was ignored in analyzing the effects of the risk factors. The tip, dorsal aspect, ventral surface, and floor of mouth on the reconstructed hemitongue had comparable static two-point discrimination when compared with the intact hemitongue. Light touch sensation was also similar in the tip and dorsal aspect of both hemitongues; however, a statistically significant difference (p < 0.05) was observed on the ventral surface and floor of mouth of the reconstructed hemitongues. Likewise, pain perception was significantly decreased in the floor of the mouth, compared with other surfaces. No clearly dependent association was established between return of flap sensation and age, tobacco use, and size of the reconstructed defect. Light touch sensation, pain, and temperature perception were significantly decreased when the patients had received postoperative radiation therapy. In addition, all four sensory tests were significantly diminished (p < 0.05) when the recipient nerve used for neurorrhaphy was a nerve other than the lingual or the inferior alveolar nerve, and also when an end-to-side nerve repair was used. Sensation recovery of the innervated radial forearm flap after hemitongue reconstruction approaches normal compared with the contralateral intact hemitongue. Lower return of sensation may be anticipated in patients who receive postoperative radiotherapy. Good recovery of sensation is predictable when either the lingual or inferior alveolar nerve is used for neurorrhaphy, in contrast to using other recipient nerves.

Adult↗
PubMed1999

Barium swallows after free jejunal transfer: should they be performed routinely?

Fistula formation after free jejunal transfer for pharyngoesophageal reconstruction is a serious complication with potentially critical consequences. Barium swallow is used postoperatively to check for anastomotic competence before feeding but has been unreliable as a predictor of leak at our institution. The objective of this study was to evaluate the role of routine postoperative barium swallow in 41 consecutive jejunal transfers. Thirty-nine patients who underwent 41 consecutive free jejunal transfers had a routine barium swallow performed between postoperative days 12 and 17. Radiologic findings and clinical outcome were evaluated and correlated. All barium swallows were reviewed by a single experienced radiologist in a blinded fashion. One total and one partial flap failure necessitated a second free jejunal transfer. Pharyngocutaneous fistulae developed after nine free jejunal transfers, of which the barium swallow was normal in four (44 percent) and showed a leak in five (56 percent). In the 32 free jejunal transfers with no clinical leaks, 6 (19 percent) had radiologic leakage of contrast. Thus, barium swallow was normal in 30 patients and showed leakage in 11 patients. Normal barium swallow correlated with uncomplicated clinical course in 26 of 30 cases. In the remaining four cases (13 percent), however, a delayed fistula developed, which was secondary to flap necrosis in one case (negative predictive value 87 percent). On the other hand, radiologic leaks corroborated clinical fistula in 5 of 11 cases (45 percent), whereas no fistula developed in 6 cases (positive predictive value 46 percent). Of the five patients with clinical fistulae, four had early leaks (within 1 week), and the barium swallow did not provide additional information. The fifth patient developed a delayed leak 2 weeks after the barium swallow. Review of these barium swallows at the time of this study reversed the initial report of leakage in three patients, improving the predictive value to 63 percent. These patients had an uncomplicated clinical course. The positive predictive value of clinical assessment alone was 63 percent. We conclude that barium studies following free jejunal transfers can be difficult to interpret, but an experienced radiologist can improve their accuracy. A normal barium swallow, however, does not ensure an uneventful clinical course. Similarly, radiologic leaks do not imply a clinical complication of fistula. Clinical judgment should therefore be exercised in initiating oral intake after free jejunal transfer. Barium swallow should be used only as an adjunct to aid in patient management.

Adolescent↗
PubMed1999

Primary reconstruction of complex midfacial defects with combined lip-switch procedures and free flaps.

Free flaps are generally the preferred method for reconstructing large defects of the midface, orbit, and maxilla that include the lip and oral commissure; commissuroplasty is traditionally performed at a second stage. Functional results of the oral sphincter using this reconstructive approach are, however, limited. This article presents a new approach to the reconstruction of massive defects of the lip and midface using a free flap in combination with a lip-switch flap. This was used in 10 patients. One-third to one-half of the upper lip was excised in seven patients, one-third of the lower lip was excised in one patient, and both the upper and lower lips were excised (one-third each) in two patients. All patients had maxillectomies, with or without mandibulectomies, in addition to full-thickness resections of the cheek. A switch flap from the opposite lip was used for reconstruction of the oral commissure and oral sphincter, and a rectus abdominis myocutaneous flap with two or three skin islands was used for reconstruction of the through-and-through defect in the midface. Free flap survival was 100 percent. All patients had good-to-excellent oral competence, and they were discharged without feeding tubes. A majority (80 percent) of the patients had an adequate oral stoma and could eat a soft diet. All patients have a satisfactory postoperative result. Immediate reconstruction of defects using a lip-switch procedure creates an oral sphincter that has excellent function, with good mobility and competence. This is a simple procedure that adds minimal operative time to the free-flap reconstruction and provides the patient with a functional stoma and acceptable appearance. The free flap can be used to reconstruct the soft tissue of the intraoral lining and external skin deficits, but it should not be used to reconstruct the lip.

Adult↗
PubMed1999

The timing and nature of neovascularization of jejunal free flaps: an experimental study in a large animal model.

The present study was designed (1) to determine whether a free jejunal transfer in a large animal model can develop collateral circulation that is adequate to maintain viability after division of the pedicle and (2) to determine the earliest time pedicle ligation is safe after transplantation. A 15-cm jejunal segment was transferred to the necks of 18 dogs weighing 25 to 35 kg. The bowel segment was inset longitudinally under the skin on one side of the neck, partially covered by the neck muscles, and the mesenteric vessels were anastomosed to recipient vessels in the neck. The proximal and distal bowel stomas were exteriorized through skin openings 12 cm apart and matured. The dogs were subjected to ligation of the vascular pedicle at different intervals: postoperative day 7 (group I, n = 3), day 14 (group II, n = 5), day 21 (group III, n = 5), and day 28 (group IV, n = 5). Blood perfusion was measured in the proximal and distal bowel stomas before pedicle division (control) and 24 hours later using hydrogen gas clearance and fluorescein dye. Bowel necrosis was analyzed using planimetry. The bowel was also stained with hematoxylin and eosin and factor VIII, and new blood vessels were counted. Mean values (+/- standard deviation) were compared with control values for each test and with normal values in the intact bowel using analysis of variance with Neumann-Keuls post-hoc test for multiple comparisons. No jejunal free flaps survived when the vascular pedicle was divided 1 week postoperatively. Bowel survival was 60 percent at 2 weeks, 83 percent at 3 weeks, and 100 percent at 4 weeks. Hydrogen gas clearance values (ml/min/100 g) were 49.6 +/- 8.7 in the mucosa of the intraabdominal jejunum and 37.9 +/- 9.4 in the jejunum that was transferred to the neck before division of the pedicle. Twenty-four hours after pedicle division, hydrogen gas clearance values were 2.8 +/- 6.4 in group I (p < 0.05), 22.4 +/- 12.4 in group II, 23.9 +/- 9.3 in group III, and 34.2 +/- 7.5 in group IV. FluoroScan readings in the transferred jejunum were 201 +/- 7.2 in the control group, 9.3 +/- 2.8 in group I (p < 0.05), 79.1 +/- 10.6 in group II, 66.2 +/- 7.3 in group III, and 164 +/- 11.9 in group IV. New vessel formation as identified by factor VIII staining correlated with increasing bowel perfusion and flap survival rate. Bowel neovascularization, perfusion, and survival increased progressively 1 week after transfer. Significant portions of the transferred bowel will neovascularize and survive as early as 2 weeks postoperatively. However, a minimum of 4 weeks before ligation of the pedicle is necessary to maximize flap perfusion and guarantee survival.

Animals↗
PubMed1998

Experience with the continuous suture microvascular anastomosis in 200 consecutive free flaps.

A variety of methods have been described for microvascular anastomosis. The continuous suture provides the same accuracy and versatility as the simple suture but can be significantly faster as well as much more hemostatic. The main argument against the use of the continuous suture is that it may narrow the caliber of the vessel lumen, and many surgeons have thus avoided its use. This technique has been used for arterial and venous anastomoses in 200 consecutive free flaps no matter what the size or the configuration of the vessels. One hundred ninety-four patients underwent 200 free tissue transfers and 410 anastomoses for a variety of oncologic-related reconstructions. A wide variety of different types of flaps, donor sites, and recipient sites were used. Of the 200 arteries (diameter, 0.5 to 5.0 mm), 90% were sutured end to end and 10% were sutured end to side. Of the 210 veins (diameter, 1.0 to 7.0 mm), 69.5% were anastomosed end to end and 30.5% end to side. There were 5 flap failures, yielding a success rate of 97.5%. Four of the failures were unrelated to the anastomosis. The reexploration rate for 200 flaps was 6.5%, with a 16.5% minor complication rate and 15.1% major complication rate. The continuous suture is a highly reliable rapid technique of microvascular anastomosis that can be used in vessels of all diameters. It is applicable for both the end-to-end and end-to-side anastomosis. It is particularly useful for vessels of disparate diameters. The success rate of reconstruction using this technique is comparable to that of most other large series using the simple suture and other methods.

Adolescent↗
PubMed1998

Fibula osteoseptocutaneous flap for reconstruction of osteoradionecrosis of the mandible.

Osteoradionecrosis of the mandible poses formidable problems for treatment. In the last 6 years, the fibula osteoseptocutaneous free flap was used in 12 cases to replace mandibles with radionecrotic damage. The presence of a pathologic fracture, exposed necrotic bone, or a persistent fistula not responding to conservative treatment were the indications for such a radical approach. Mandible defects after resection were around 8.0 cm long, and in all cases intraoral mucosa, skin, or both were included with the bone excision. All vascularized fibula osteoseptocutaneous flaps transplanted were successful with good primary bone healing. Adequate facial symmetry and improvement in oral function was achieved. No evidence of osteoradionecrosis recurrence was observed after a mean follow-up period of 3 years and 9 months. The advantages of using the fibula osteoseptocutaneous flap for mandible reconstruction are numerous, and good aesthetic and functional results can be obtained when it is used for reconstruction after radical excision of osteoradionecrotic lesions.

Adult↗
PubMed1998

Primary insertion of osseointegrated dental implants into fibula osteoseptocutaneous free flap for mandible reconstruction.

Twelve patients with segmental mandibular defects were reconstructed with fibula osteoseptocutaneous flaps and simultaneous placement of osseointegrated implants. Decision to perform this procedure was based on the facts that all patients had benign diseases, did not require postoperative radiotherapy, were in good general and oral conditions, and were psychologically motivated. A total of 34 fixtures was inserted in the first stage. Eight patients underwent second stage surgery, which consisted of connection of the implant abutments to the fixtures and the use of palatal mucosal grafts around the implants. Final dental prostheses were fixed 1 month later in seven patients, at this time. All flaps survived after surgery, and no implant failure was observed after a mean follow-up period of 25 months. Only one fixture was not used during the subsequent stage and was left as a sleeper. Fixed dental prostheses were used in five patients and removable overlay prostheses in the other two. Chewing function was recovered between 4 and 6 weeks after the start using the definitive dental prosthesis. In contrast to previous results, we conclude that excellent results can be achieved when this combined procedure is used in carefully selected patients. In addition, it is confirmed that the fibula osteoseptocutaneous flap is a versatile, reliable composite tissue that facilitates primary placement of osseointegrated dental implants during mandible reconstruction, thus allowing full oral rehabilitation in a shorter period of time.

Adolescent↗
PubMed1998

Reconstruction of total maxillectomy defects with preservation of the orbital contents.

Reconstruction after total maxillectomy with preservation of the orbital contents is technically more challenging than when the maxillectomy is combined with orbital exenteration. Reconstruction of such defects should (1) provide support to the orbital contents, (2) obliterate any communication between the orbit and nasopharynx, (3) reconstruct the palatal surface, and (4) achieve facial symmetry and a good aesthetic result. We report our experience in performing reconstructive surgery on 14 patients who had a total maxillectomy and preservation of the orbital contents using nonvascularized bone grafts for reconstruction of the orbital floor and maxilla, in conjunction with a soft-tissue free flap or pedicled muscle flap. The orbital floor was reconstructed using split ribs in six cases (42.9 percent), split calvaria in six cases (42.9 percent), and iliac crest graft in two cases (14.3 percent). A myocutaneous rectus abdominis free flap was used for soft-tissue reconstruction and resurfacing of the palatal mucosa in twelve patients (85.7 percent), and a temporalis muscle transposition was used in two elderly patients (14.3 percent). One patient died 2 days after surgery. Mean follow-up and aesthetic and functional results were assessed in the remaining 13 patients a minimum of 6 months postoperatively. In 9 of these 13 patients (69.2 percent), postoperative radiotherapy was administered. No reexplorations or free flap failures were observed. One rectus flap developed partial necrosis of the skin island intraorally without affecting the final result. All patients had adequate functional vision. One patient had a mild vertical dystopia; there were no cases of enophthalmos. Ectropion was the most common undesirable result and was present in 10 of 13 cases (76.9 percent). It was graded as mild in four cases (40.0 percent), moderate in four cases (40.0 percent), and severe in the remaining two cases (20.0 percent). Speech was considered normal in six cases (46.2 percent), near normal in six cases (46.2 percent), and intelligible in one case (7.7 percent). Chewing function was considered good (soft to unrestricted diet) in all cases except for one patient who was only able to eat a pureed diet. Aesthetic results after immediate reconstruction were considered good in nine cases (69.2 percent) and fair in four cases (30.8 percent). Primary reconstruction of total maxillectomy defects with orbital content preservation remains a complex problem without a perfect solution. The combination of nonvascularized bone grafts for orbital/maxillary reconstruction with a soft-tissue free flap is a safe, reliable, and effective method of maximizing postoperative functional and aesthetic results.

Adult↗
PubMed1998

Use of a nitric oxide precursor to protect pig myocutaneous flaps from ischemia-reperfusion injury.

Nitric oxide is a radical with vasodilating properties that protects tissues from neutrophil-mediated ischemia-reperfusion injury in the heart and intestine. Previous studies in our laboratory suggested that L-arginine, a nitric oxide precursor, can protect skin flaps from ischemia-reperfusion injury. In this study, we examined the effects of L-arginine on the survival of myocutaneous flaps in a large animal model and established whether this effect was mediated by nitric oxide and neutrophils. Two superiorly based 15 x 7.5 cm epigastric myocutaneous island flaps were dissected in 15 Yorkshire pigs weighing 45 to 50 kg. One of the flaps was subjected to 6 hours of arterial ischemia and then reperfused for 4 hours (ischemia-reperfusion flaps), whereas the other flap was used as a non-ischemic control (non-ischemia-reperfusion flaps). The flaps were divided into four groups: control non-ischemia-reperfusion flaps that received only saline (group I); ischemia-reperfusion flaps that were treated with saline (group II); and flaps treated with either L-arginine (group III) or Nomega-nitro-L-arginine methylester (L-NAME), a nitric oxide synthase competitive inhibitor, plus L-arginine in equimolar amounts (group IV). These drugs were administered as an intravenous bolus 10 minutes before the onset of reperfusion, followed by a 1-hour continuous intravenous infusion. Full-thickness muscle biopsies were taken at baseline, 3 and 6 hours of ischemia, and 1 and 4 hours of reperfusion. The biopsies were evaluated by counting neutrophils and measuring myelo-peroxidase activity. At the end of the experiment, skeletal muscle necrosis was quantified using the nitroblue tetrazolium staining technique, and a full-thickness biopsy of each flap was used for determination of water content. Statistical analysis was performed using analysis of variance and the Newman-Keuls test. Non-ischemia-reperfusion flaps showed no muscle necrosis. Ischemia-reperfusion flaps treated with saline had 68.7 +/- 9.1 percent necrosis, which was reduced to 21.9 +/- 13.6 percent with L-arginine (p < 0.05). L-NAME administered concomitantly with L-arginine demonstrated a necrosis rate similar to that of saline-treated ischemia-reperfusion flaps (61.0 +/- 17.6 percent). Neutrophil counts and myeloperoxidase activity after 4 hours of reperfusion were significantly higher in ischemia-reperfusion flaps treated with L-NAME and L-arginine as compared with the other three groups (p < 0.05). Flap water content increased significantly in ischemia-reperfusion flaps treated with saline and L-NAME plus L-arginine versus non-ischemia-reperfusion flaps (p < 0.02) and L-arginine-treated ischemia-reperfusion flaps (p < 0.05). There was no difference in flap water content between ischemia-reperfusion flaps treated with L-arginine and non-ischemia-reperfusion flaps. Administration of L-arginine before and during the initial hour of reperfusion significantly reduced the extent of flap necrosis, neutrophil accumulation, and edema due to ischemia-reperfusion injury in a large animal model. This protective effect is completely negated by the use of the nitric oxide synthase blocker L-NAME. The mechanism of action seems to be related to nitric oxide-mediated suppression of ischemia-reperfusion injury through neutrophil activity inhibition.

Animals↗
PubMed1998

Single versus double arterial anastomoses in combined second- and third-toe transplantation.

Combined second and third toe transplantation is one good option for reconstruction of multiple digit amputation. However, the use of one or two arteries for pedicle anastomoses, which may influence the vascular complication and success rate, has never been addressed in the literature. This study includes a retrospective review of 57 combined second and third toe transplantation in 54 patients performed from February of 1983 through December of 1996. Group I, composed of 41 transplantations, underwent one arterial anastomosis, and group II, composed of 16 transplantations, underwent double arterial anastomoses during surgery if there were two recipient arteries available or whenever the second and third toes showed inadequate blood perfusion after one arterial anastomosis. In group I, 10 transplantations (24.4 percent) required re-exploration with a success rate of 92.7 percent (38 out of 41 transplantations). In group II, only one transplantation (6.2 percent) required re-exploration with successful flap salvage. The success rate was 100 percent for group II. Because the re-exploration and success rates between groups I and II were not statistically significant according to two-tailed Fisher's exact test, the combined second and third toe transplantation is a reliable procedure using either single or double arterial anastomoses.

Adolescent↗
PubMed1997

The extended, pedicled rectus abdominis free tissue transfer for head and neck reconstruction.

The rectus abdominis musculocutaneous free tissue transfer has become a mainstay of reconstruction for large defects in the head and neck. The length of the deep inferior epigastric vessel is traditionally accepted to be 8 to 10 cm from its origin to its entrance into the rectus muscle. This pedicle is usually not long enough for reconstruction of the upper midface, forehead, and cranial base if vascular anastomosis to the neck vessels is necessary. Vein grafts have been recommended under these circumstances. We have been able to extend the length of the vascular pedicle by intramuscular dissection of the lateral branch of the deep inferior epigastric artery and veins in 26 clinical cases. The dissection is carried along the posterior surface of the muscle, up to the first tendonous inscription. Intraoperative measurements of the pedicle length before (6.9 +/- 1.0 cm) and after (13.7 +/- 2.0 cm) dissection, as well as in 17 fresh cadavers (34 muscles), demonstrate that the pedicle length can be increased safely from 7.8 +/- 0.5 cm to 17.7 +/- 0.52 cm (range, 15.8 to 19.1 cm). This long-pedicled flap has been used successfully in 26 patients for reconstruction of different types of defects in the head and neck, without using vein grafts.

Adolescent↗