Ayhan Comert

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 individuals arm length. Using this safe area should provide a safe exposure for the axillary nerve during shoulder operations.

Ultrastructural evaluation of pulsed radiofrequency and conventional radiofrequency lesions in rat sciatic nerve

BACKGROUND PRF treatment has recently been described as minimally neurodestructive alternative to radiofrequency heat lesions. Patients with some pain syndromes in whom the pain could not be controlled by alternative techniques may be treated using PRF. In the present study, our main goal was to evaluate and compare the ultrastructure of peripheral nerve tissue that was heated by PRF, CRF with 42 degrees C, and CRF with 70 degrees C. METHODS Forty-five male rats were divided into 5 groups. In PRF group and CRF with 42 degrees C group, the sciatic nerve was heated at a temperature of 42 degrees C for 120 seconds. As a positive control, some rat sciatic nerves were treated with CRF lesions at 70 degrees C. The rats were kept alive for 21 days and then killed. Tissue was evaluated with transmission electron microscope, and grading was done to the groups. RESULTS The unmyelinated nerve fibers were ultrastructurally normal in all groups. The results of myelinated axons indicated that PRF group had better grades, and CRF with 70 degrees C group had the worst grade. Especially, comparison of the group of PRF and CRF with 42 degrees C revealed significant difference. In PRF group, none of the myelinated axons showed severe degeneration findings, and most of the damaged myelinated axons showed only separation in myelin configuration. CONCLUSIONS PRF treatment may cause separation in myelinated axons. However, it seems that all changes were reversible. The present study supports the hypothesis that pulsed RF treatment does not rely on thermal injury of neurologic tissue to achieve its effect.

Implant stability and bone density: assessment of correlation in fresh cadavers using conventional and osteotome implant sockets

OBJECTIVE To compare the primary stability of implants placed in conventional and osteotome sites and to evaluate the level of correlation between cutting torque measurements, resonance frequency analysis (RFA), and bone density. MATERIALS AND METHODS Eight human femoral heads were scanned with computed tomography for bone density measurements as Hounsfield units (HU), and individualized computed tomography-based surgical stents were prepared for placement of implants. Five implant sockets were prepared in each collum (CoF), caput (CaF), and trochanter (Tr-MM) section of the femoral heads using the conventional drilling technique or by a combination of drilling and use of an osteotome. Cutting-torque values (CTV) of the implants were measured by a manual torque wrench, followed by determination of implant stability quotients (ISQ) by RFA. RESULTS The CTVs of implants were similar in the conventional group, but different in the osteotome group (P<0.05). There was a general tendency toward achieving higher CTV and ISQ values in CoF than CaF and Tr-MM (P<0.05), and measurements in CaF and Tr-MM were comparable (P>0.05). The mean HU of sites were similar, although CoF had higher HU values (P>0.05). CTV of implants in CaF and Tr-MM and ISQ values in CoF in the conventional groups were higher than those in the osteotome groups (P<0.05). The correlation between CTV and HU in Tr-MM was significant in the osteotome group, although no other correlations between CTV, ISQ, and HU could be detected (P>0.025). CONCLUSIONS Conventional placement led to higher implant stability than the drilling and osteotome technique used in the study. No correlation could be found between CTV, RFA, and bone density.

Inhibition of pentylenetetrazol-induced seizures in rats by prostaglandin D2

This study was undertaken to evaluate the role of brain PGD2 activity during PTZ induced seizures in rats. Potentiation of endogenous PGD2 activity caused an anti-convulsant effect. Thus, after PGD2 injection (5 microg/icv) the latency of generalized tonic clonic convulsions was prolonged. ZK 118.182, a stable analogue of PGD2, dose-dependently inhibited the incidence and the intensity of seizures when injected at doses of 1-100 ng/icv. But on the other hand, inhibition of PGD2 activity either by a D-type PG receptor antagonist (AH 6809; 50 ng/icv) or by a PGD synthase inhibitor (sodium selenite; 0.2 microg/icv) produced a proconvulsant effect by increasing the incidence and the intensity of the seizures. These findings indicate that endogenous PGD2 activity in the brain may have a specific inhibitory role for the initiation and propagation of PTZ induced seizures in rats.

Use of pimecrolimus to prevent epidural fibrosis in a postlaminectomy rat model

OBJECT Epidural fibrosis is the scar tissue formed over the dura mater after a laminectomy. Extensive epidural fibrosis may be an important underlying cause of failed back syndrome. Pimecrolimus, an ascomycin derivative, is one of the new classes of immunomodulating macrolactams and was specifically developed for the treatment of inflammatory diseases. This study examined the preventive effects of the local application of pimecrolimus in minimizing spinal epidural fibrosis in a rat laminectomy model. METHODS Thirty Wistar rats were divided into 3 equal groups: control, mitomycin C (MMC), and pimecrolimus groups. Each rat underwent a laminectomy at the L-3 lumbar level. In the experimental groups, a cotton pad soaked with MMC (0.5 mg/ml) or 5 mg pimecrolimus was placed on the exposed dura mater. No treatment was performed in the control group rats. Thirty days after surgery, the rats were killed and the dura mater thickness, epidural fibrosis, and arachnoidal involvement were quantified. RESULTS The mean dura thickness was measured at 9.28 +/- 3.39 microm in the MMC group and at 8.69 +/- 2.32 microm in the pimecrolimus group, compared with 14.70 +/- 4.14 microm in the control group. In addition, the epidural fibrosis and arachnoidal involvement were reduced significantly in the treatment groups compared with the control group. CONCLUSIONS In this animal model, it was shown that locally applied pimecrolimus effectively reduces epidural fibrosis and dural adherence in rats that underwent lumbar laminectomy. Mitomycin C was equally effective as pimecrolimus in reducing epidural fibrosis and dural adherence in this study.

Ultrasound-guided obturator nerve block: a sonoanatomic study of a new methodologic approach.

BACKGROUND: Obturator nerve block is one of the most technically challenging regional anesthesia techniques. Recently, the characteristics of the nerve have been described using ultrasound. However, clinical application of proximal ultrasound-guided obturator nerve block on patients has not been reported. In this study, we used ultrasound to describe the anatomical localization of the obturator nerve and its two branches in cadavers, volunteers, and also patients. METHODS: A hyperechoic triangular shape formed by the superior pubic ramus, posterior margin of the pectineus muscle and anterior aspect of the external obturator muscle containing the obturator vessels and nerve was defined by ultrasound imaging in cadavers. In eight volunteers, bilateral obturator nerve images were obtained and the distances to specific landmarks (femoral artery, femoral vein, and pubic tubercle) were recorded. Ultrasound-guided obturator nerve block was further performed in 15 patients by using the previously defined approach. The final distance of the needle tip to the femoral artery, distances between the needle insertion point to the pubic tubercle and the depth of needle insertion were recorded. RESULTS: The rates of common obturator nerve, anterior and branching obturator nerve pattern visibility with ultrasound were determined in 12/16, 13/16, and 7/16 sites in volunteers, respectively. Mean (sd) values of critical landmarks obtained from volunteers were obturator nerve-femoral vein 12.9 ± 2.9 mm and obturator nerve-pubic tubercle 19.9 ± 2.6 mm. Mean measurements obtained from patients were: femoral artery- needle tip 18.5 ± 2.4 mm, needle depth 48.3 ± 10.4 mm, pubic tubercle- needle insertion point (horizontal) 18.8 ± 2.0 mm, and pubic tubercle- needle insertion point (vertical) 21.1 ± 2.9 mm. Visual analog scale scores obtained from patients at 1 and 24 h were lower compared to baseline values (P < 0.001). Ninety-three percent (14 of 15) of the patients reported satisfaction from the block. CONCLUSIONS: Landmarks defined in this clinical trial can be used in patients for obturator nerve block with ultrasound guidance.

Posterior osseous bridging of C1

The sulcus of the vertebral artery is located behind the lateral mass of the atlas and in some cases is converted into a foramen by anomalous ossification known as the posterior ponticulus (osseous bridge). This study involved anatomical observations of 158 isolated anatomical specimens of dry C1 vertebrae. The incidence and types of posterior osseous bridging were identified for the 158 dry samples of atlas vertebrae. In nine (5.6%) dry C1 vertebrae, partial osseous bridging was detected (bilaterally in eight vertebrae and unilaterally on the left in one). Complete osseous bridging (arcuate foramen) was observed in six (3.8%) dry C1 vertebrae (bilaterally in one vertebra, unilaterally on the left in three, and on the right in two). Awareness of the types of posterior osseous bridging of C1 in craniocervical junction surgery is essential, and may be helpful in surgical interventions in this region.

Olfactory functions after transsphenoidal pituitary surgery: Endoscopic versus microscopic approach

Olfactory disturbances could be observed following transsphenoidal pituitary surgeries. To our knowledge, no previous comparative studies on olfactory functions after transsphenoidal endoscopic and microscopic approaches have been performed.

Maxilla Allograft for Transplantation : An Anatomical Study

Introduction:The aim of this study is to present an anatomic study and a dissection technique to prepare maxilla graft for transplantation. Methods:Six fixed adult human cadavers were used for dissection of the maxilla grafts. Retrospective reviews of archives of 10 MRI and 5 angiographies of the maxillary region were performed to demonstrate the vascular and soft tissue anatomy of this area. Results:We have harvested maxilla graft as a single unit (larger type of Le Fort II) based on arterial and venous pedicle ready for transplantation. MRI evaluation revealed the vascular structures in the masticatory space and its anterior pterygomaxillary extension. Angiographic observations have demonstrated the arterial blood supply of the maxillary region, which lies within the pterygomaxillary region that we have included in the graft. Conclusions:We are presenting a method for harvesting of the maxilla graft, with vascular supply based on certain anatomic landmarks.

Endoscopic Anatomy of Sphenoid Sinus for Pituitary Surgery

Endoscopic endonasal transsphenoidal approach to the sellar region yields an alternative to classical microsurgical approaches. Endoscopes provide images that differ from microscopic view. This study aimed to highlight surgical landmarks and their anatomical relationships for pituitary surgery through endoscopic perspective. Ten sides of five adult cadaveric heads with red‐colored latex injected arteries were evaluated. Endoscopic dissections were performed and measurements were done in the sphenoid sinuses before and after the removal of bony structures in all the aspects. Endoscopic vision of the sellar region enabled a wide panoramic perspective and detailed inspection. The measurements, in general, indicated the variations in the bony structures and soft tissues. The width of the pituitary, which is the distance between the medial margins of the carotid prominences, was measured as 21 ± 2.5 mm and the distance between the medial margin of the carotid prominences at the lower margin of the pituitary was 18 ± 3.1 mm. After the bony structures were removed, further measurements were done. The width of the pituitary, which is the distance between the medial margins of the anterior curvature of the ICA, was measured as 23.2 ± 3 mm, while the distance between the posterior curvature of the ICA was 19.7 ± 4.9 mm. Endoscopic view provided superior detailed visualization of the close relationships between pituitary gland, internal carotid arteries, and optic nerves. This facilitated exact evaluation for variations, which could result in more effective and safe surgery. However, these variations again emphasize the necessity of preoperative radiological evaluation in each case. Clin. Anat. 21:627–632, 2008.