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Biomedical subjects

Ibrahim Tekdemir

Publications and source records attributed to Ibrahim Tekdemir.

At least 19 recordsLinked to original sources
PubMed2007

The axillary sheath and single-injection axillary block.

Failure to block the terminal nerves of the brachial plexus, the circumferential type of incomplete axillary brachial plexus block, is the main problem of the single-injection technique. Two studies were carried out to observe the internal anatomy of the axillary sheath and the effect of different volumes of dye injected into the sheath in cadavers. In our first study, the internal arrangement of the axillary sheath and its septae were examined microscopically by slicing the sheath longitudinally and transversely. In the second study, boluses of 10, 20, and 40 cc of methylene-blue were injected into one of the compartments of the axillary sheath. The axillary sheath was dissected out and sliced transversely to observe the spread of the dye in the injected and in the adjacent compartments. The specimens of the axillary sheath were then opened longitudinally and the septae excised and examined at x10 magnification to see the effect of the various volumes of the injection bolus. This study shows that septae from the deep surface of the axillary sheath form compartments for each nerve. The septae function as barriers under physiologic conditions. By increasing the injected volume of solutions, bubble-like defects are produced in the septae in the compartments into which leakage was demonstrated.

Aged↗
PubMed2007

Surgical anatomy of the external branch of the superior laryngeal nerve.

Palsy of the external branch of the superior laryngeal nerve (EBSLN) during thyroid surgery is an important complication reported with varying frequency. This study was carried out to investigate the relationship between the EBSLN, the upper part of the thyroid gland and the inferior constrictor muscle of the pharynx (IC), and also to define consistent landmarks for identifying and preserving the EBSLN. Forty neck halves of 20 cadavers were dissected. Measurements were obtained between the crossing point of the EBSLN with the superior thyroid artery (STA) and the upper pole of the thyroid gland, the point where EBSLN penetrates the IC and the inferior thyroid tubercle, and the middle point of the oblique line of the thyroid cartilage, and the EBSLN. In 22.5%, the EBSLN crossed the STA more than 1 cm above the upper pole of the thyroid gland (Type I of Cernea et al. [1992a] Head Neck 14:380-383). In 60%, the EBSLN crossed the STA less than 1 cm above the upper pole of the thyroid gland (Type IIa of Cernea et al. [1992a] Head Neck 14:380-383). In 17.5%, the EBSLN crossed the STA under the upper pole of the thyroid gland (Type IIb of Cernea et al. [1992a], Head Neck 14:380-383). In 22.5%, the full course of the nerve was superficial to the IC (Type 1 of Friedman et al. [2002] Arch Otolaryngol Head Neck Surg 128:296-303). In 67.5%, the nerve penetrated the IC (Type 2 of Friedman et al. [2002] Arch Otolaryngol Head Neck Surg 128:296-303). In 10%, the nerve could not be identified at the lateral side of the IC (Type 3 of Friedman et al. [2002] Arch Otolaryngol Head Neck Surg 128:296-303). In conclusion, it is possible to identify the nerve superficial to the IC in 90% of specimens on average. Knowledge of the relationship between the EBSLN, IC, inferior thyroid tubercle, oblique line of the thyroid cartilage and the sternothyroid muscle will be useful for the surgeon in avoiding unexpected complications.

Adult↗
PubMed2006

Review of complications due to foramen ovale puncture.

We aim to evaluate the mechanisms responsible for complications during trigeminal rhizotomy via foramen ovale puncture. Ten dry skulls and 10 skull-base specimens were investigated in the present study. In cadaveric skull-base specimens, the anatomical relationships between the foramen ovale, mandibular nerve and Gasserian ganglion and the surrounding neurovascular structures were investigated intradurally. The distance between the foramen ovale and Gasserian ganglion was measured as 6 mm. The abducent nerve, adjacent to the anterior tail of the petrolingual ligament, was observed passing along the lateral wall of the cavernous sinus. Advancement of the catheter more than 10 mm from the foramen ovale is likely to damage the internal carotid artery and the abducent nerve at the medial side of the petrolingual ligament. Thermocoagulation of the lateral wall of the cavernous sinus may damage the cranial nerves by heat, giving rise to pareses.

Anatomy, Regional↗
PubMed2006

Relationship between the posterior cerebral artery and the cisternal segment of the oculomotor nerve.

The aim of this study was to evaluate the relationship between the cisternal segment of the oculomotor nerve and the posterior cerebral artery and its branches. The oculomotor nerve and the posterior cerebral artery of 15 cadaver brains (30 hemispheres) were examined using a surgical microscope. The dorsal portion of the cisternal segment of the oculomotor nerve had a close relationship with the P(1) and P(2) segments of the posterior cerebral artery in 100% of cases, the thalamoperforating arteries in 97%, the collicular arteries in 97%, the short circumferential arteries in 33% and the posterior medial choroidal arteries in 20%. The proximal portion of the nerve had a close relationship with the P(1) segment of the posterior cerebral artery, the thalamoperforating arteries, the collicular arteries and the short circumferential arteries, whereas the distal portion had a close relationship with the P(2) segment of the posterior cerebral artery and the posterior medial choroidal arteries. The oculomotor nerve was perforated by various arteries in different portions. These arteries were the thalamoperforating arteries in 10% of the hemispheres, the collicular arteries in 16% and the short circumferential arteries in 11%. It can be concluded that the dorsal portion of the cisternal segment of the oculomotor nerve has a close relationship with the branches arising from the P(1) and P(2) segments of the posterior cerebral artery. These arteries supply the cisternal segment of the oculomotor nerve.

Arteriovenous Malformations↗
PubMed2006

Course of the innervation supply of medial head of triceps muscle and anconeus muscle at the posterior aspect of humerus (anatomical study).

INTRODUCTION: In elbow surgery; posterior side of joint has been described as the front door for accessing the elbow pathologies. Triceps splitting, triceps reflection, posterolateral Kocher, posteromedial Bryan-Morrey, modified MacAusland transolecranon approaches are the well known posterior surgical approaches. In the English literature, release and transposition of ulnar nerve on the medial side was fully described in posterior approaches. We believe that there was a need to identify the structures at the lateral aspect of the elbow while an iatrogenic injury may inversely effect an excellent radiological result. Therefore, we exposed the detailed innervation supply to the anconeus muscle and medial head of triceps muscle and tried to show possible denervation sites of these two structures during posterior approaches. MATERIALS AND METHODS: This study was performed on 14 elbows in formalin-preserved 7 cadavers. We exposed the course of the innervation supply to the medial head of triceps muscle and anconeus muscle and tried to show possible denervation sites of these two structures during posterior approaches. The branching pattern of radial nerve innervating anconeus muscle and its deriving level from radial nerve was identified. Distance from a vertical line which is passing through lateral epicondyle to branching point was measured. RESULTS: The mean distance of the branching point of the nerve to medial head of triceps muscle and anconeus was 168.3 mm (range 130.36-185.4). The nerve to anconeus muscle ran along the posterior aspect of the humerus from the horizontal line passing through lateral epicondyle at a distance of 142.20 mm (range 153.72-136.41) medial to olecranon and at a distance of 47.45 mm (range 77.13-30.14) lateral to olecranon. CONCLUSION: Although splitting the fibers of triceps proximaly increases the exposure of the posterior humerus, innervation of the lateral portion of the medial head of triceps muscle and anconeus muscle may be jeoparadized. Therefore, surgeons who have interest in elbow surgery; (1) should revise the course of the nerve to medial head of triceps and anconeus muscle, (2) be aware of possible iatrogenic injury of the extensor muscles of the elbow via transtricipital approaches, (3) try to choose a more conservative posterior surgical approach.

Elbow↗
PubMed2006

Examination of the skin perforators of the posterior tibial artery on the leg and the ankle region and their clinical use.

BACKGROUND: There are many treatment alternatives for reconstruction of leg and foot defects. One of these treatment alternatives includes local flaps. A detailed understanding of the blood flow of the leg region is essential for producing new alternatives for the reconstruction of defects of this region. METHODS: The leg and foot region blood flow was examined on 11 fresh cadavers, and perforators of this region were examined in three zones. Perforator numbers and their diameters were defined at this region. It was determined in cadaver studies that especially zones I and II were more suitable for the planned flaps based on perforators of the posterior tibial artery. In a clinical study that accompanies this anatomical study, eight patients underwent reconstruction by flaps based on the perforators of the posterior tibial artery. RESULTS: Patients were followed for 3 to 14 months. In three patients, venous drainage problems had developed, and in one of them, partial flap loss had developed. This partially necrosed region was left to heal by secondary intention. Venous drainage problems resolved in 5 to 7 days in the two remaining patients. No other complications were seen. CONCLUSION: Regarding the results of the clinical study, the authors observed that this flap can provide the desired soft-tissue support for defects that expose the bones, tendons, and neural and vascular bundles.

Adult↗
PubMed2006

Towards the limit of quantifying low-amplitude strains on bone and in coagulum around immediately loaded oral implants in extraction sockets.

The purpose of this study was to quantify strains in coagulum around immediately loaded oral implants in extraction sockets at the ex vivo level. Bilateral maxillary premolar teeth of two fresh human cadavers were extracted and psi 4.1 x 12 mm Straumann TE implants were placed in the sockets of first and second premolars by utilizing mesio-distal and palatal anchorage, respectively. Installation torque value (ITV) of each implant was measured by a custom-made torque wrench and resonance frequency analyses (RFAs) were undertaken to determine intraosseous stability. Upon abutment connection, a gold coping allowing the placement of a miniature load cell to contact the underlying solid abutment was fabricated. A linear strain gauge was connected to the coping at a distance for strain measurements in coagulum around the implant neck in the extraction socket. Linear strain gauges were also bonded on the labial marginal bone of each extraction socket. Strain measurements were performed at a sample rate of 10 kHz simultaneously monitored from a computer connected to data acquisition system and under a maximum load of 100 N on each implant with or without human coagulum in the extraction socket. Low-amplitude strains were measured around immediate implants. The increase in load increased strains on labial marginal cortical bone around implants (P < 0.05). Bone strains were higher on the implant loaded, when coagulum was present in the bone defects (P < 0.05). Strains within coagulum around mesiodistally anchored implants were higher than palatally anchored implants (P < 0.05). The type of implant on anchorage and presence of coagulum has an impact mechanotransduction to buccal marginal bone around immediate implants.

Blood Coagulation↗
PubMed2006

The coexistence of temporomandibular disorders and styloid process fracture: a clinical report.

This clinical report describes the diagnosis and treatment of a patient with both temporomandibular disorders (TMD) and styloid process fracture. The presence of tender muscles of mastication, facial pain, especially upon awakening, frequent grinding sounds, and tooth attrition indicated a diagnosis of TMD with bruxism as a possible etiological factor. However, the preliminary diagnosis of styloid process fracture based on the patient's sensation of a foreign body in the throat and some discomfort when turning the head was confirmed using radiography. The styloid process fracture was treated using conservative nonsurgical therapy, and an occlusal splint was used to treat the TMD. The patient's symptoms were significantly reduced at the 12-month follow-up visit.

Adult↗
PubMed2006

Biomechanical aspects of initial intraosseous stability and implant design: a quantitative micro-morphometric analysis.

PURPOSE: The objective of this biomechanical study was to explore the effect of bone micro-morphology on initial intraosseous stability of implants with different designs. MATERIAL AND METHODS: Straumann and Astra Tech dental implants were placed into anterior and posterior regions of completely edentulous maxilla and mandible of a human cadaver. Experiments were undertaken to quantify initial implant stability and bone micro-morphology. Installation torque values (ITVs) and implant stability quotients (ISQs) were measured to determine initial intraosseous implant stability. For quantification of relative bone volume and micro-architecture, sectioned implant-bone and bone core specimens of each implant placement site were consecutively scanned and trabecular bone was analyzed in a micro-computed tomography (micro-CT) unit. Experimental outcomes were evaluated for correlations among implant designs, initial intraosseous implant stability and bone micro-structural parameters. RESULTS: ITVs correlated higher with bone volume fraction (BV/TV) than ISQs, at 88.1% and 68.9% levels, respectively. Correlations between ITVs and micro-morphometric parameters were significant at the 95% confidence level (P<0.05) while ISQs were not. Differences in ITVs, ISQs and BV/TV data in regards to implant designs used were not significant at the 95% confidence level (P>0.05). CONCLUSION: Bone micro-morphology has a prevailing effect over implant design on intraosseus initial implant stability, and ITV is more sensitive in terms of revealing biomechanical properties at the bone-implant interface in comparison with ISQ.

Alveolar Process↗
PubMed2006

Is there a safe area for the axillary nerve in the deltoid muscle? A cadaveric study.

BACKGROUND: Several authors have defined a variety of so-called safe zones for deltoid-splitting incisions. The first aim of the present study was to investigate the distance of the axillary nerve from the acromion and its relation to arm length. The second aim was to identify a safe area for the axillary nerve during surgical dissection of the deltoid muscle. METHODS: Twenty-four shoulders of embalmed adult cadavers were included in the study. The distance from the anterior edge of the acromion to the course of the axillary nerve was measured and was recorded as the anterior distance. The same measurement from the posterior edge of the acromion to the course of the axillary nerve was made and was recorded as the posterior distance for each limb. Correlation analysis was performed between the arm length and the anterior distance and the posterior distance for each limb. The ratios between arm length and the anterior and posterior distances were calculated for each case and were recorded as an anterior index and a posterior index. RESULTS: The average arm length was 30.40 cm. The average anterior distance was 6.08 cm, and the average posterior distance was 4.87 cm. There was a significant correlation between arm length and both anterior distance (r = 0.79, p < 0.001) and posterior distance (r = 0.61, p = 0.001). The axillary nerve was not found to lie at a constant distance from the acromion at every point along its course. The average anterior index was 0.20, and the average posterior index was 0.16. CONCLUSIONS: The present study describes a safe area above the axillary nerve that is quadrangular in shape, with the length of the lateral edges being dependent on the individual's arm length. Using this safe area should provide a safe exposure for the axillary nerve during shoulder operations.

Acromion↗
PubMed2006

A neurosurgical view of anatomical variations of the distal anterior cerebral artery: an anatomical study.

OBJECT: The vascularization pattern of the anatomy of the distal anterior cerebral artery (ACA) remains a subject of debate. The authors provide detailed information about the distal ACA and shed light on issues concerning it that have not previously been adequately discussed. METHODS: Fifty adult human brains (100 hemispheres) were obtained during routine autopsies. Cerebral arteries were separately cannulated and injected with latex. The vascularization patterns of the cortical branches and the variations of the arteries were investigated. The authors found that the distal ACA supplied all the inner surfaces of the frontal and parietal lobes and a median of one third of the outer surfaces. The origin of the arteries from the main trunk and their exit angles affected the vascularization patterns of the hemispheres. The authors redefine controversial terminology regarding the callosomarginal artery. CONCLUSIONS: In each hemisphere, the vascularization pattern of the distal ACA is different to a greater or lesser extent. An awareness of this fact will contribute significantly to surgical interventions.

Anterior Cerebral Artery↗
PubMed2005

Anatomical variations as potential risk factors for ulnar tunnel syndrome: a cadaveric study.

The aim of this study was to assess the anatomical variations, especially the anomalous muscles passing through Guyon's canal and the fibrous arch forming the piso-hamate hiatus, which may play a role in ulnar tunnel syndrome. We have also focused on the relation of these structures with specific concern to the ulnar nerve. Nineteen embalmed cadavers (37 hands and forearms) were dissected. A fibrous arch extending between the pisiform and the hook of the hamate was observed in 21 hands. In majority of the cases flexor digiti minimi muscle was found to originate only from this arch. An anomalous muscle was disclosed in six hands with four of them passing through the piso-hamate hiatus with the deep branch of the ulnar nerve. In two of four cases, the superficial branch of the ulnar nerve was also accompanying the deep branch of the ulnar nerve beneath the anomalous muscle and through the piso-hamate hiatus. Because these anomalous muscles were generally found to course through the piso-hamate hiatus with the branches of the ulnar nerve, we conclude that the distal portion of the Guyon's canal has a relatively higher risk for ulnar nerve entrapment. We believe that surgeons operating on this region should take into account these various anatomic structures.

Cadaver↗
PubMed2005

Anatomic pattern of the terminal branches of posterior interosseous nerve.

To understand the lesion of the terminal branches of posterior interosseous nerve (PIN), an anatomic study was carried out. Thirty adult cadaver arms were dissected and the anatomic pattern of the nerve was documented. The distance between the point at which the nerve divides into branches and the distal edge of the supinator were measured, as well as the length of each nerve branch to its muscle-entering sites. The number of branches innervating each muscle was recorded. It was found that the PIN was branching to multiple short branches and a single deep long branch after leaving the supinator muscle with great morphometric and schematic variances.

Adult↗
PubMed2005

The vascular anatomy of the abductor digiti minimi and the flexor digiti minimi brevis muscles.

PURPOSE: The abductor digiti minimi (ADM) and the flexor digiti minimi (FDM) brevis muscles could be used as flaps with their low functional morbidity, especially in severe crushed injuries of the hand. The vascular anatomy of both of the muscles were investigated to classify the muscles according to the Mathes-Nahai classification. METHODS: Nine cadavers embalmed with formaline were dissected under loupe magnification (x4) from the wrist proximally to the proximal phalanx of the small finger distally, delineating the branches of the ulnar artery along the ADM and FDM muscles. RESULTS: The dissections and the microangiography of the muscles revealed 1 major and 2 minor pedicles. Both of the muscles could be classified as type II muscles according to the Mathes-Nahai classification. CONCLUSIONS: The vascular pattern of the ADM muscle has been described previously, this study explored the vascular anatomy of the FDM muscle. The information regarding the vascular supplies of these muscles could be of help to the clinician when manipulating the muscles. The FDM muscle could be a suitable alternative for the ADM muscle in opponensplasty. When the pedicles are preserved the muscles could be used--based proximally or distally.

Adult↗
PubMed2005

Arterial vascularization of primary motor cortex (precentral gyrus).

BACKGROUND: The precentral gyrus (PG) is the primary motor area and is one of the most eloquent brain regions of neurosurgical interest. Although the arterial supply to the PG is generally known, contributions from different arterial branches such as the anterior cerebral artery (ACA), posterior cerebral artery (PCA), and middle cerebral artery (MCA) have not been comprehensively studied. The aim of the present study was to provide detailed information about the arteries of the PG. METHODS: Twenty adult human brains (40 hemispheres) were obtained, and ACA, MCA, and PCA were separately cannulated and injected with latex. The PG was identified. RESULTS: The ACA supplied the medial one third and the MCA supplied the lateral two thirds of the PG. The PCA did not reach the PG in any of the hemispheres. In 16 hemispheres (40%), the callosomarginal artery and, in 13 hemispheres (32.5%), the pericallosal artery were dominant for the medial one third of the PG. In 11 hemispheres (27.5%), equal dominance was observed. MCA branches at the lateral tip of the PG were classified into precentral, central, and postcentral groups. In 29 hemispheres (72.5%), the central group, and in 4 hemispheres (10%), the precentral group were dominant for the lateral two thirds of the PG. In 7 hemispheres (17.5%), the precentral and central groups were equally dominant. No dominance was identified for the postcentral group. CONCLUSION: In each hemisphere, the PG was supplied by different vascularization patterns of ACA and MCA. The present study is the first to describe and discuss these details. Therefore, awareness of this pattern will provide a great contribution to surgical interventions.

Adult↗
PubMed2005

Retropharyngeal space and lymph nodes: an anatomical guide for surgical dissection.

Identification of the alar fascia is the key part of surgical dissection of the retropharyngeal lymph nodes (RPLNs). In cases where mandibulotomy is not performed for the removal of the primary tumor and/or the posterior pharyngeal wall is not incised, the medial or lateral approaches described in this paper can be performed. Surgical dissection of the RPLNs may improve prognosis and locoregional control in oropharyngeal, hypopharyngeal and cervical esophageal carcinomas. There have been no previous anatomical studies concerning landmarks and approaches for the surgical dissection of the RPLNs. This study was designed to illustrate the fascial anatomy of the retropharyngeal region (RPR), provide anatomical guidelines for RPLN dissection and describe and compare approaches for surgical removal of the RPLNs. Twelve fixed cadavers were used. Slices were obtained from the necks of the first three cadavers and the RPRs of the slices were dissected under an operating microscope. The other nine cadavers were dissected in a surgical position to expose the RPLNs and the fasciae of the RPR. In the coronal plane, the alar fascia divides the space between the buccopharyngeal and prevertebral fasciae into two compartments and constitutes the posterior border of the retropharyngeal space, which contains the RPLNs. The alar fascia, an important landmark for reaching the RPLNs, can be identified by the cervical sympathetic trunk, superior sympathetic ganglion and superior laryngeal nerve. Two approaches can be performed to remove the RPLNs, namely medial or lateral to the internal and external carotid arteries, internal jugular vein and vagus nerve.

Cadaver↗
PubMed2005

Reconstruction of proximal nasal defects with island composite nasal flaps.

There are few local nasal flap options for repair of proximal nasal defects. Absence of suitable donor sites and the large dimensions of the defects limit the use of local nasal flaps in this region. Regional paranasal flaps may not be suitable in these cases because of color, texture, and donor-site scars. The composite procerus muscle and nasal skin flap, which is vascularized by the dorsal nasal branch of the angular artery, can be a useful treatment modality for proximal nasal reconstruction. Seven patients were successfully treated using the composite nasal flaps. The maximal size of the defects was 2.4 cm. In one case, the composite nasal flap was readvanced to close a new defect resulting from reexcision. The composite nasal flap has several advantages in reconstruction of proximal nasal defects. Reconstruction is performed with the same tissue and the donor defect is closed primarily. The composite nasal flap can be moved in multiple directions and has great mobility to reach every point of the proximal part of the nose with axial blood supply. Furthermore, it can be easily readvanced without additional morbidity in case of reexcision.

Aged↗