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Biomedical subjects

Omer Ozkan

Publications and source records attributed to Omer Ozkan.

At least 19 recordsLinked to original sources
PubMed2006

Venous supercharging of heterodigital artery flap.

BACKGROUND: The heterodigital artery island flap is a popular method of reconstruction for finger defects. Postoperative venous congestion is a common problem. METHODS: The authors present a technique to augment venous drainage of the flap. Briefly, the flap is harvested along with a dorsal vein that is then anastomosed to a recipient vein in an end-to-end fashion, after flap transfer and insetting. Using this technique, seven patients were operated on, ranging in age from 5 to 35 years (average age, 23 years). RESULTS: All flaps survived with no postoperative flap congestion, fully satisfying the reconstructive requirements. By this modification, skeletonization of the digital artery of the flap pedicle is safe if that approach is preferred, since there is no need to harvest periarterial fat for venous drainage. CONCLUSIONS: Providing good harmony with conventional methods and microsurgery, inclusion of a vein with the heterodigital artery island flap allows a more reliable and safer reconstructive choice for finger defects. Such a modification converts the unconventional venous circulation of the heterodigital artery island flap to a more physiologic one.

Adolescent↗
PubMed2006

Reversed anterior interosseous flap.

Reversed flaps from the forearm have been firmly established for hand coverage. Each has its own advantages and disadvantages. The reversed anterior interosseous flap is one option with special advantages in hand reconstruction. From January 2002 to July 2003 we used this flap in five consecutive male patients aged between 36 and 59. The defects were located on the first web space (2), on the dorsal side of the thumb (1), on the first metacarpal bone (1), and on the volar side of the wrist (1). Flap size was between 6 x 3 cm and 11 x 7 cm. All flaps healed without any problem and no complication was observed during the postoperative period. The major advantage of this flap is the preservation of the main arteries of the upper limb. Other advantages are as follows: good texture and colour for hand reconstruction, satisfactory rotation arc, and availability of composite and fascial flaps. Besides its advantages, the major disadvantages are unsightly donor area scar and the need for meticulous technique. As a conclusion, we found this flap very useful in hand reconstruction for coverage of small and moderate sized soft tissue defects of the hand.

Adult↗
PubMed2006

Free microvascular transfer of the reverse ileo-colon flap with ileocaecal valve valvuloplasty for reconstruction of a pharyngoesophageal defect: Indication and usage of the 'funnel flap'.

The authors have designed a method of reconstruction for high pharyngeal and oesophageal defects that potentially avoids many of the disadvantages related to size mismatch at the proximal and distal end of oesophageal defects that are encountered with the use of free jejunal and colon flaps, respectively. An ileo-colon flap was used to reconstruct this type of defect where the ascending colon was anastomosed to the pharyngeal end and the ileum was anastomosed to the oesophageal end. Both sides were perfectly matched in circumference and minimal manipulation was necessary at both ends of the flap. A detailed description of the surgical technique is depicted and a case presented. While this procedure solves some of the problems encountered when dealing with this type of defect, it nevertheless does have some disadvantages and technical nuisances that are detailed and discussed in this report.

Colon↗
PubMed2006

Strength properties of concrete incorporating coal bottom ash and granulated blast furnace slag.

Coal bottom ash (CBA) and fly ash (FA) are by-products of thermal power plants. Granulated blast-furnace slag (GBFS) is developed during iron production in iron and steel plants. This research was conducted to evaluate the compressive strength property and some durability characteristics of concrete incorporating FA, CBA, and GBFS. FA is used as an effective partial cement replacement; CBA and GBFS are used as partial replacement for fine aggregate without grinding. Water absorption capacity, unit weight and compressive strengths in 7, 28, and 90-day ages were assessed experimentally. For these experiments, concrete specimens were produced in the laboratory in appropriate shapes. The samples are divided into two main categories: M1, which incorporated CBA and GBFS; and M2, which incorporated FA, CBA, and GBFS. Remarkable decreases are observed in compressive strength and water absorption capacity of the concrete; bulk density of the concrete is also decreased. It can be concluded that if the content of CBA and GBFS is limited to a reasonable amount, the small decreases in strength can be accepted for low strength concrete works.

Carbon↗
PubMed2006

Dysphagia [corrected] due to solitary jejunal diverticulum after free jejunal transfer for reconstruction of the cervical oesophagus.

The free jejunal flap has been widely used in clinical practice for the restoration of the cervical oesophagus, but a variety of complications still pose problems. The purpose of this report is to present a rare complication of the jejunal flap. A diverticulum of the jejunal segment, causing severe dysphagia, occurred 4 years after flap transfer in a 50-year-old man who underwent oesophageal reconstruction due to severe stricture following caustic ingestion. The patient was treated successfully by resection of the diverticulum. When examining a patient with unidentified symptoms in the neck or dysphagia after cervical oesophageal reconstruction with free jejunal transplant the possibility of small bowel diverticula should be borne in mind in order to prevent serious life-threatening complications that may arise from it.

Anastomosis, Surgical↗
PubMed2006

Unique superiority of microsurgical repair technique with its functional and aesthetic outcomes in ring avulsion injuries.

Although ring avulsion injuries are not common, when they do occur their management is still a challenging problem in reconstructive surgery. In this report, we present our microsurgical experiences with Kay's class III and IV ring avulsion injuries. A total of six patients with ring avulsion injuries were operated on between 2000 and 2004. Three patients were in class III with inadequacy of both arterial and venous circulation, and the remaining three were in class IV. The study consisted of four male and two female patients whose ages ranged from 23 to 43 (mean age 32). Average ischaemic time was 2.2 h (range 1-4 h). The ring finger was involved in all cases and microsurgical repair was performed using axillary block anaesthesia. The bone was detached at the level of the distal interphalangeal joint and soft tissues at the proximal phalanx level with the preserved proximal interphalangeal joint and flexor digitorum superficialis tendon in all cases. Because the zone of injury is more extensive, we debrided the avulsed digital artery over a long distance, and used long interpositional vein grafts radically in all patients. Venous drainage was accomplished by performing at least two vein anastomoses using vein grafts when necessary. Both digital nerves were repaired primarily after debridement. Results indicated that microsurgical repair had a success rate of 100%. The authors conclude that microsurgical reconstruction of ring avulsion injuries with intact proximal interphalangeal joint and flexor digitorum superficialis tendon yields superior results, both functionally and aesthetically, even in complete amputation.

Adult↗
PubMed2006

Single osteotomized iliac crest free flap in anterior mandible reconstruction.

While the iliac crest flap provides a natural contour for the lateral segment of the mandible, for the anterior segment en bloc, the use of the iliac graft, even harvested in a V shape, fails to yield a three-dimensional natural-shaped reconstruction. In this report, we present our experience with reconstruction of the anterior segment of the mandible using a single osteotomized free iliac crest flap in 5 patients. The study comprised 4 male patients and 1 female patient, their ages ranging between 34-82 years. In all patients, composite iliac osteomusculocutaneous flaps were harvested based on the deep circumflex iliac artery in the standard manner, and the bony segment of the flap was divided into two segments, performing a single osteotomy. The fixation of bone segments was performed in new positions, sliding the segments in different planes to provide the original shape of the resected mandible segment, and in a manner appropriate to the defect. The overall flap success rate was 100%. In no cases were wound infections or hematomas observed. X-rays showed bone healing without resorption. In conclusion, the use of a single osteotomy for an iliac crest flap in the reconstruction of the anterior segment of the mandible is a simple and safe procedure, and provides a natural and acceptable jaw appearance. The risk of devascularization is quite low when compared with the multiple osteotomy procedure, and it does not need to be fixed with complex devices such as reconstruction plates or external fixators.

Adult↗
PubMed2006

Principles for the management of toe-to-hand transfer in reexploration: toe salvage with a tubed groin flap in the last step.

Failure of the transferred toe in toe-to-hand transplantations is a catastrophe and a devastating complication for both the patient and the reconstructive surgeon, as in all microvascular tissue transfers. Management of the toe transfer in the case of reexploration is still a challenging issue, even for experienced microsurgeons. In this report, basic principles for a successful outcome are proposed, based on experience with more than 500 toe-to-hand transfers. Although the requirements for each case may vary, technical details and some basic salvage strategies receive special emphasis. When faced with a problem, the first step should be focused on perceiving the problem differently from under completely normal conditions. The problem may occur at any stage of the procedure. The basic orientations are focused on vasospasm, a thrombus inside the lumen, possible intimal damage that may be caused during the surgery or by a thrombus, or technical failures regarding anastomoses. After all possible revisional procedures have been carried out, if the proper arterial inflow and/or venous outflow are still not provided, or if the general health status of the patient is no longer suitable for additional lengthy procedures, the tubed groin flap can be used to salvage the transferred toe. Between 1996-2004, eight tubed groin flaps were used to salvage transferred toes in the last step of the revisional procedure, with satisfactory results. In conclusion, close follow-up and prompt reexploration when needed are both essential to salvaging transferred toes. Proper surgical strategies and decision-making in reexploration are highly important factors in achieving a successful outcome. In prolonged and recurrent revisional steps, the creation of a tubed flap by means of a reliable flap is an effective procedure as the last step of the salvage procedure.

Adult↗
PubMed2006

Repair of buccal defects with anterolateral thigh flaps.

The ideal reconstructive method for the buccal mucosa should provide durable, stable coverage and a natural contour, while simultaneously minimizing morbidity of both the defect and donor sites. Since the first report of the anterolateral thigh flap in 1984, it has become one of the most commonly used flaps for the reconstruction of various soft-tissue defects. From March 2004-April 2005, 24 free anterolateral thigh flaps were used to reconstruct buccal defects, including the retromolar trigone and as far as the oral commissure, and in some cases with extension to the neighboring palatal region and tongue. The study comprised 1 female and 23 male patients, with ages ranging from 26-63 years (mean age, 45.8 years). Two flaps required reoperation due to vascular compromise, and both were salvaged with arterial and venous anastomosis revisions, giving an overall success rate of 100%. Primary thinning of the flap was performed in 10 cases. In 2 cases, additional vastus lateralis muscle was included in the flap to fill the large defect. In 2 cases, marginal necrosis with dehiscence of the flap was observed, one of these patients having a history of atherosclerosis and diabetes mellitus (marginal skin necrosis and infection of the donor area were also observed in this patient). In 2 patients, seroma collection was observed in the neck at the dissection site. Chart reviews showed that most patients had a history of betel-nut chewing (95.8%) or a combination of smoking and betel-nut chewing (79.2%). During the follow-up period of 4-12 months, a sufficient level of mouth-opening with interincisal distances of 34 mm, 44 mm, and 48 mm was achieved in all 3 cases reconstructed after release of the trismus. Although it has some variations in the vascular pedicle, irregularity in derivation from the main vessels, and minimal morbidity of the donor site, the anterolateral thigh flap, with its evident functional, structural, and cosmetic advantages, can be considered an excellent and ideal flap option, and a first choice for most buccal defects.

Adult↗
PubMed2006

Guidelines for the optimization of microsurgery in atherosclerotic patients.

We review the pathogenesis of atherosclerosis and the issues that must be taken into consideration when performing microsurgery in atherosclerotic patients. Atherosclerosis is a systemic disease, and may affect the success of microsurgery. Atherosclerotic patients have a tendency toward thrombosis, because the nature of the arteries is changed. Such patients are usually old and have additional medical problems. To increase the success rate of microsurgery in atherosclerotic patients, special precautions should be considered. Patients must be evaluated properly for the suitability of microsurgery. The microsurgical technique requires a meticulous approach, and various technical tricks can be used to avoid thrombosis. Recipient-vessel selection, anastomotic technique, and the use of vein grafts are all important issues. Prophylactic anticoagulation is recommended in severely atherosclerotic patients. Close monitoring of the patient and flap is necessary after the operation, as with routine microvascular free-tissue transfers. We conclude that atherosclerosis is not a contraindication for microsurgery. If the microsurgeon knows how to deal with the difficulties in atherosclerotic patients, microsurgery can be performed safely.

Anticoagulants↗
PubMed2006

Neuromuscular and neuromusculocutaneous flaps in the rat.

Since the introduction of flaps based on the vascular structures of the cutaneous nerves, these have gained increasing popularity in reconstructive surgery. The purpose of this study is to describe a new concept in which the flap is supplied solely by the intrinsic vasculature of a motor nerve. A total of 94 Wistar rats weighing 200-250 g were used in this experiment, which was divided into three sections. In section I, the neural anatomy of the posterior thigh region was investigated. In section II, the flap study using experimental and control groups, was performed. In the experimental group neuromuscular and neuromusculocutaneous flaps were created. The biceps femoris muscle was harvested based solely on its motor nerve as a neuromuscular flap, and together with its overlying skin it was similarly raised as a neuromusculocutaneous flap. In the control group, conventional muscle and musculocutaneous flaps were harvested based on the caudal femoral-popliteal artery vascular axis, and a graft subgroup was created ligating both the constant vascular structure and the motor nerve. In section III, with the intention of augmenting the survival areas of neuromuscular and neuroumusculocutaneous flaps, a surgical delay procedure was applied. On postoperative day 7, the viability of all flaps was evaluated using direct observation, microangiography, and tetrazolium blue stain techniques. The results of the anatomic studies demonstrated a consistent motor nerve arising from the sciatic nerve to the biceps femoris muscle with evident perineural vasculature. Average muscle viability levels of neuromuscular, neuromusculocutaneous, delayed neuromuscular, delayed neuromusculocutaneous, conventional muscle and musculocutaneous flaps were 20.6 +/-7.58, 22.4 +/- 4.21, 86.4 +/- 6.14, 85 +/- 4.21, 89.6 +/- 4.48, and 88.0 +/- 5.51%, respectively. Survival levels of the skin paddles of the neuromusculocutaneous, delayed neuromusculocutaneous, and conventional musculocutaneous flaps were calculated as 13 +/- 17.51, 67 +/- 30.29, and 97+/-4.21%, respectively. In the graft subgroup the viability of muscle and skin paddle was almost nil. In conclusion, our new flap model in a favored laboratory animal is of benefit to researchers in providing a means for future various types of investigations into this new concept. The technique might be considered in further experimental research studies and appropriate clinical situations.

Animals↗
PubMed2006

Deltopectoral flap revisited: role of the extended flap in reconstruction of the head and neck.

The extended deltopectoral flap is still the best choice in selected cases. During the period 1987-2004, 34 patients required reconstruction of the head and neck using this flap. Twenty-nine had had one or more failed attempts at microsurgical reconstruction after excision of cancer. Five were treated primarily. The flap was divided at least three weeks after the primary operation. All 34 survived, and there were no donor site complications. Twenty-seven patients had an uncomplicated outcome, but the remaining seven required later closure or skin grafting, usually under local anaesthesia, for complications. The extended deltopectoral flap has been used successfully to provide stable coverage of defects in the head and neck and should remain in the armamentarium of reconstructive microsurgeons.

Adult↗
PubMed2006

Posterior tibial artery flap in poliomyelitis patients with lower extremity paralysis.

BACKGROUND: Poliomyelitis is a disease that can render affected individuals incapacitated to a variable degree. A normal lifespan is expected and therefore the patients deserve every effort at curative cancer resection and reconstruction. Those with lower extremity paralysis rely heavily on their upper limbs and torso for ambulation; therefore, their compromised limbs may be a better donor site for flaps. METHODS: All poliomyelitis patients with lower extremity paralysis over a 20-month period who underwent head and neck reconstruction were selected for a retrospective review. Perioperative complications were noted and outpatient follow-up was performed. RESULTS: Three patients underwent reconstruction of defects using the posterior tibial artery flap. Two patients required reconstruction of a buccal defect and one patient required soft palate reconstruction. All patients healed without complications and none required reexploration. At a mean follow-up of 10 months, there was no incidence of donor limb vascular compromise, cold intolerance, or long-term paresthesias. CONCLUSIONS: The posterior tibial artery free flap has been used successfully in the past; however, its popularity has been limited because of sacrifice of the posterior tibial artery. Nevertheless, in patients with lower extremity paralysis, this flap may fulfill the requirements of a thin, pliable flap with minimal hair that has a long pedicle and a reliable blood supply. Most importantly, the use of this flap obviates the need to use flaps that fulfill the same requirement, such as forearm flaps, that would be taken from patients' functioning limbs.

Adult↗
PubMed2006

A supermicrosurgical flap model in the rat: a free true abdominal perforator flap with a short pedicle.

BACKGROUND: Perforator flaps have recently gained considerable popularity in reconstructive surgery, and their importance and advantages over conventional flaps have been widely accepted. Given the improvements in microsurgical techniques, researchers have encouraged the search for further perforator flap sources, such as a perforator flap with a short pedicle only. The purpose of this study was to describe a true perforator flap model with a short vascular pedicle in the abdominal region in the rat. METHODS: Twenty-six adult Sprague-Dawley rats weighing 400 to 500 g were used. In 10 rats, the perforator vascular anatomy of the abdominal region was determined by anatomic dissection. In the remaining 16 rats, a true abdominal perforator-based flap was created based on a short segment of deep epigastric vessels. In eight rats, the flap was transferred to the groin region as a free flap, and anastomosis was performed between the artery and vein of the flap and the superficial inferior epigastric artery and vein of the recipient site. In addition, in two of these flaps, the long thoracic vein of the flap was anastomosed to the femoral vein. In the remaining eight rats, the flap was transferred to the groin region, but in this group anastomosis was not performed. The latter group was designated as the control group. RESULTS: The skin islands of seven free perforator flaps survived completely, and the one remaining flap was determined to be necrotic. All the flaps in the control group underwent complete necrosis. CONCLUSIONS: Not only is the free abdominal perforator flap a reliable and true perforator flap model for future physiological, biological, and pharmacological studies, it is also an excellent self-controlled supermicrosurgical training model for learning proper techniques, meticulous intramuscular dissection of true perforator flaps, and anastomosis of small-caliber vessels.

Anastomosis, Surgical↗
PubMed2006

Free tensor fascia lata perforator flap as a backup procedure for head and neck reconstruction.

Free tissue transfer is an essential part of the head and neck reconstruction. Despite several flap options, free perforator flaps have become very popular for head and neck. Anterolateral thigh perforator flap has multiple advantages among other options and is preferred by most of the reconstructive microsurgeons. Besides its advantages, sometimes it is impossible to harvest an anterolateral thigh perforator flap, and the surgeon has to shift to another option. Between January 2002 and June 2005, 5 tensor fascia lata perforator flaps were used for head and neck reconstruction because anterolateral thigh perforator flap could not be elevated due to absence or insufficient musculocutaneous perforators. Only 1 flap was reexplored and salvaged by redoing the venous anastomosis. All flaps survived without any other problem. Donor sites were covered by split-thickness skin grafts in 4 patients and closed directly in 1 of them. Doppler examination is important in planning of anterolateral thigh perforator; if the signals of the perforators are absent or very weak, the surgeon can shift to another flap. This decision may also be made during the operation when insufficient perforators are seen. Based on our experience, tensor fascia lata perforator flap is a safe alternative when anterolateral thigh perforator harvest is not possible. Tensor fascia lata perforator flap can be harvested from the same anatomic region with almost same morbidity.

Adult↗
PubMed2006

The effect of ischemic preconditioning on secondary ischemia in skin flaps.

Ischemic preconditioning is a useful manipulation to reduce the undesirable effects of ischemia. The beneficial results of this phenomenon against ischemia-reperfusion have been seen in different flap models; however, all these studies have focused on primary ischemia. In this study, we investigated the effects of ischemic preconditioning on secondary ischemia in a skin flap model. We used the 6- x 3-cm-sized epigastric skin flap in 40 Wistar rats. In all animals, primary global ischemia of 2 hours was followed by 4 hours of either arterial or venous secondary ischemia 24 hours after the primary ischemia and ischemic preconditioning (IP) was tested in this protocol. Ischemic preconditioning was performed by 2 cycles of 15 minutes of repeated ischemia/reperfusion periods. The animals were allocated into 4 groups: group 1 (n = 10 animals): primary ischemia (2 hours) + secondary arterial ischemia (4 hours); group 2 (n = 10 animals): IP + primary ischemia (2 hours) + secondary arterial ischemia (4 hours); group 3 (n = 10 animals): primary ischemia (2 hours) + secondary venous ischemia (4 hours); group 4 (n = 10 animals): IP + primary ischemia (2 hours) + secondary venous ischemia (4 hours). Flap viability was assessed 1 week after the surgical procedure, and surviving flap area was recorded as a percentage of the whole flap area. Group 1 was compared with group 2, and group 3 was compared with group 4 to evaluate the effects of ischemic preconditioning against secondary arterial and venous ischemia. t test and Mann-Whitney rank sum tests were used for statistical analysis. There were statistical differences both between groups 1 and 2 and groups 3 and 4. The results revealed that ischemic preconditioning was an effective procedure to reduce the flap necrosis as a cause of secondary ischemia in skin flaps.

Animals↗