Mustafa Asim Aydin

Force deficits in skeletal muscle after delayed reinnervation.

Using a rat hindlimb model, the authors tested the hypothesis that, in muscles reinnervated after long-term denervation, atrophy-dependent and atrophy-independent mechanisms operate independently to produce force deficits. In adult rats, gastrocnemius muscles were subjected to denervation via tibial nerve transection. Reconstruction of the nerve lesion was delayed for periods ranging from 2 weeks to 1 year. After a minimum recovery period of 6 months after nerve repair, muscle mass and maximum isometric tetanic force were measured and specific force was calculated for each muscle (n = 40 muscles from 23 animals). After recovery, observed deficits in muscle mass and maximum tetanic force were directly proportional to the denervation interval. On the other hand, the deficit in specific force was not proportional to the denervation interval; all groups in which the nerve reconstruction was delayed for a month or longer demonstrated a deficit of 30 percent to 50 percent. These data support our hypothesis that, after prolonged denervation followed by reinnervation, the magnitude of the deficit in whole muscle force does not parallel the deficit in specific force. These data support the idea that mechanisms governing muscle atrophy are independent of those resulting in specific force deficits.

Avascular necrosis of the mandibular condyle causing fibrous ankylosis of the temporomandibular joint in sickle cell anemia.

Avascular necrosis, which most commonly affects the femoral head, is a well-recognized entity in orthopedic surgery. Maxillofacial surgeons have recently recognized that a similar process may also be at work in the temporomandibular joint because of the involvement of the mandibular condyle. Avascular necrosis of the mandibular condyle in association with sickle cell anemia is an infrequent finding. In this report, a patient with avascular necrosis of the mandibular condyle in the late stage causing fibrous ankylosis of the temporomandibular joint in sickle cell anemia is presented.

Reconstruction of Soft Tissue Defect of Lower Extremity With Free SCIA/SIEA Flap

Free tissue transfer is the most important means of soft tissue reconstruction for the lower extremity. However, cosmetic results and donor site morbidity are only of secondary concern of lower extremity reconstruction. In our efforts to obtain the best possible outcome for patients, as our first priority we chose free superficial circumflex inferior artery (SCIA)/superficial inferior epigastric artery (SIEA) flap over other free flap options in the soft tissue reconstruction of lower extremity because of some advantages. Over the past 3 year, 25 patients underwent lower extremity reconstruction with free SCIA/SIEA flap (n = 27). Twenty-six of 27 flaps were successful (96%), 6 required emergent postoperative re-exploration of the anastomosis, and 1 failed. Although secondary debulking procedure was performed for some flaps (n = 3), most flaps had acceptable thickness for functional and esthetic outcomes especially in the pretibial, ankle, and foot defect reconstruction with an average of 1-year follow-up. Based on our results, free SCIA/SIEA flap has the following advantages in soft tissue reconstruction of lower extremity: (1) large flaps may be harvested for extensive defect and/or to reach recipient artery for passing zone of injury; (2) if necessary, final flap debulking may be performed by surgical procedure using local anesthesia; (3) the donor site is closed in a similar manner to abdominoplasty incision so that excellent cosmetic result may be achieved.

Flow-through Free Latissimus Dorsi Flap for Reconstruction of Injured Limbs: Evaluation of Hemodynamic Effects on Extremity Circulation

Management of vascularized injured extremity requires careful reconstruction for continuity of leg circulation. Protection of the remaining intact vessels during free flap transfer provides condition for blood flow maintenance in the distal extremity. Latissimus dorsi muscle has the correct vessel anatomy for applying flow-through flap because it protects recipient vessel integrity during soft tissue reconstruction. Flow-through flap circulation may cause decreasing blood flow in the recipient artery and steal phenomenon in distal circulation although the main vessel remains intact. The purpose of this study was to describe blood flow changes in the recipient artery, flap pedicle, and distal leg circulation at early and long-term follow-up periods. For this purpose, evaluations of blood flows by using Doppler ultrasonography were performed in 2 vascularized injured extremities which were reconstructed with flow-through free latissimus dorsi musculocutaneous flaps. The results demonstrate that flow-through flaps in our vascularized injured extremity did not disturb distal leg circulation in spite of increased blood flow in the recipient and pedicle arteries.

Lymphoscintigraphic drainage patterns of the auricle in healthy subjects

In lymphoscintigraphies of the head and neck, multiple injections around a tumor result in variable drainage to multiple nodal basins. We undertook this study in healthy subjects to test whether single injections at specified points in the auricle display single predictable pathways and predict visualization of parotid sentinel lymph nodes (SLNs).

Versatility of free SCIA/SIEA flaps in head and neck defects.

Reconstruction of head and neck defects may require replacement of the bony structures, external soft tissue, and intraoral mucosa. Most cases, including maxillary defects, often require repair using only soft tissue flaps. Recently, the authors used free superficial circumflex iliac artery/superficial inferior epigastric (SCIA/SIEA) flaps for head and neck reconstruction. This was their first choice over other free flaps due to its versatile advantages. Fifteen patients underwent head and neck reconstruction with free SCIA/SIEA flaps (n = 16). No flap loss was observed; however, emergency vascular reanastomosis was performed in 3 cases to restore the blood supply in compromised flaps. Flap thinning and secondary debulking procedures were performed in 4 cases. The functional and aesthetic results were deemed as acceptable in all patients. Based on our results, we believe that the free SCIA/SIEA flap is useful for soft tissue defect reconstruction in the head and neck. It has the following advantages: (1) Large flap elevation is possible for reaching distant recipient vessels, (2) Two surgical teams may work at the same time preparing the donor and recipient regions, and (3) The flap design uses an abdominoplasty incision, which has minimal donor site morbidity.

Fat tissue as a new vascular carrier for prefabrication in reconstructive surgery: experimental study in rats

Several vascular carriers for different tissues were used for the purpose of fat tissue prefabrication. However, the inguinal fat pad in rats can be elevated with a vascular pedicle and considered as a vascular carrier. To the best of our knowledge, the fat tissue in rats as a vascular carrier has not been reported in any experimental studies to date. In our study, we aimed to describe a new prefabrication model in rats in which skin prefabrication was accomplished using the inguinal fat pad as a vascular carrier. Inguinal fat pads in rats were elevated over a superficial epigastric vessel pedicle in the pilot study. The contralateral inguinal fat pads were prepared as grafts. After 1 week, we compared the histopathological findings of the inguinal fat pad flaps and grafts and determined that the inguinal fat pad can be safely elevated over the vascular pedicle. In the experimental group, bilateral vascularised inguinal fat pads were transferred to the lower abdomen for skin prefabrication. After 3 weeks, bilateral fat-skin composite flaps including prefabricated lower abdomen skin were elevated over the vascular pedicles. One side was used as a composite flap while pedicle of the other side was transected at its origin at the femoral vessels to create the composite graft. Composite flap and graft were inserted at their original positions. One week later, the composite flaps were stained with India ink, perfused by fluorescein, and filled with contrast material for microangiographic study. In the histological examination, fat and skin tissues of the composite flaps were viable while those of the composite grafts were necrotic. Based on these findings, we can conclude that the fat tissue as a vascular carrier can be successfully used for tissue prefabrication in plastic surgery.

Muscle–nerve–muscle neurotization for the reinnervation of denervated somatic muscle

Abstract Muscle–Nerve–Muscle (MNM) is the reinnervation of a denervated (recipient) muscle via a nerve graft inserted into the belly of an innervated (donor) muscle. MNM is studied for the reinnervation of intrinsic denervated somatic skeletal muscle by evaluating both restored muscle contractile ability and innervation state. In a rat model, muscle function is tested following MNM neurotization from an innervated (donor), extensor digitorum longus muscle to a denervated (recipient), peroneus digit quinti (PDQ) muscle. PDQ muscle cross-sections labeled for neural cell adhesion molecule protein (NCAM), a marker for fiber denervation. MNM neurotization results in the recovery of PDQ muscle force generating capacity (58% of Normal-control) and a significantly lower percentage of residual muscle fiber denervation (38% denervated) compared with the Denervated-control (79% denervated) group. MNM neurotization reinnervates 62% of the previously denervated muscle fibers in the PDQ muscle. No decrement in force capacity is observed in the donor EDL muscle. Nerve grafting for MNM neurotization may restore modest contractile function to denervated muscle and reinnervate relatively more denervated muscle fibers than the Denervated-control.

Thrombotic effect of purposeful back-wall stitch for different suture locations and vessels in rats.

Many microsurgeons experience inadvertent back-wall stitch as a cause of immediate anastomotic failure. To investigate this factor as a possible cause of delayed arterial anastomotic failure that does not appear in the operation room, a purposeful back-wall stitch (PBWS) model of microarterial anastomosis was applied in various configurations on femoral and carotid arteries of rats. Carotid (n = 28) and femoral (n = 28) artery groups were equally divided into 4 different subgroups according to the type of PBWS. Control subgroups had no PBWS. Thirty-degree, 60-degree, and 90-degree subgroups had PBWS located at 30, 60, and 90 degrees, respectively. Patencies were assessed at 60 minutes and 24 hours. Immediate milking test demonstrated normal anterograde refilling in all anastomoses. PBWS increased thrombosis in femoral arteries, while it did not increase it in the carotid at either evaluation times. The only significant difference was between 90 degrees PBWS and the control subgroup irrespective of the vessel factor in 24 hours. Histologic examination supported absence of thrombosis, as suggested by surgical examination. This may show that small-sized arteries are more inclined to thrombosis compared with larger ones and the thrombosis risk increases as the inadvertent back-wall stitch is more centrally located. Contrary to general notion that the inadvertent back-wall stitch causes immediate thrombosis, thromboses later than 1 hour, and even patent anastomoses in 24 hours, were observed in femoral and carotid artery groups. This study suggests that the inadvertent back-wall stitch should also be considered as a possible cause of late anastomotic problems.

Misdiagnosed widespread eosinophilic granuloma of the mandible.

Abstract Eosinophilic granuloma is the most common expression of Langerhans cell histiocytosis and corresponds with typical bone lesions. Early clinical signs can occur in the mandible and can cause extensive destruction of the periodontal tissues. Pathologic fracture is an unusual finding. A case of misdiagnosed eosinophilic granuloma in a 45-year-old man treated with free fibula flap and implant-supported overdenture prosthesis is reported. Free fibula flap with dental implants is a safe and reliable method for comprehensive functional and aesthetic mandibular defect reconstruction.