The relationship between ethmoidal foramina and orbital fat herniation.

BACKGROUND: The aims of this study are to determine the incidence and more frequent localizations of orbital fat tissue herniation accompanying dehiscences in the medial orbital wall and to investigate the relationship between orbital fat tissue herniations and the anterior and posterior ethmoidal foramina. METHODS: One thousand two hundred patients who had undergone computed tomography with a preliminary diagnosis of sinusitis and who had no previous facial, orbital, paranasal sinus surgeries or history of trauma were retrospectively analyzed. The localization of the ethmoidal foramina and orbital fat tissue herniations were marked. In patients with orbital fat tissue herniation, the relationship between the localization of orbital fat tissue herniation and the anterior and posterior ethmoidal foramina was investigated. RESULTS: The incidence of orbital adipose tissue herniation in our study was 7.9%. Of the 98 herniations on the bilateral medial orbital wall, 60 were in zone 3, and the most common herniation site was zone 3. A statistically significant difference was noted between the localization zone of the anterior ethmoidal foramen and the localization zones of orbital fat tissue herniations (Fisher's exact test, p < 0.001). DISCUSSION: Zone 3 is the weakest area of the medial orbital wall, and zone 3 is the most prone to herniation of fat tissue. The association of orbital fat tissue herniations with the anterior ethmoidal foramen is extremely common. Being cognizant of this finding may help a surgeon better estimate the anatomical view to be met before functional endoscopic sinus surgery as well as to minimize the risk of possible orbital complications, especially anterior ethmoidal artery injury.

The relationship between ethmoidal foramina and orbital fat herniation.

Background/aim: The aims of this study are to determine the incidence and more frequent localizations of orbital fat tissue herniation accompanying dehiscences in the medial orbital wall and to investigate the relationship between orbital fat tissue herniations and the anterior and posterior ethmoidal foramina. Material and methods: One thousand two hundred patients who had undergone computed tomography with a preliminary diagnosis of sinusitis and who had no previous facial, orbital, paranasal sinus surgeries or history of trauma were retrospectively analyzed. The localization of the ethmoidal foramina and orbital fat tissue herniations were marked. In patients with orbital fat tissue herniation, the relationship between the localization of orbital fat tissue herniation and the anterior and posterior ethmoidal foramina was investigated. Results: The incidence of orbital adipose tissue herniation in our study was 7.9%. Of the 98 herniations on the bilateral medial orbital wall, 60 were in zone 3, and the most common herniation site was zone 3. A statistically significant difference was noted between the localization zone of the anterior ethmoidal foramen and the localization zones of orbital fat tissue herniations (Fisher's exact test, p < 0.001). Conclusion: Zone 3 is the weakest area of the medial orbital wall, and zone 3 is the most prone to herniation of fat tissue. The association of orbital fat tissue herniations with the anterior ethmoidal foramen is extremely common. Being cognizant of this finding may help a surgeon better estimate the anatomical view to be met before functional endoscopic sinus surgery as well as to minimize the risk of possible orbital complications, especially anterior ethmoidal artery injury.

Redefining the collateral system between the superior mesenteric artery and inferior mesenteric artery: a novel classification.

AIM: The aim of this study was to evaluate the arterial collateral vasculature between the superior mesenteric artery and the inferior mesenteric artery (IMA) from a surgical perspective. METHOD: A total of 107 fresh adult cadavers (94 male) were studied with emphasis on the vascular anatomy of the left colon. Dissections were carried out mimicking the anterior resection technique. The vasculature of the left mesocolon and the collaterals between the superior mesenteric artery and the IMA with respect to their relationship to the inferior mesenteric vein (IMV) were assessed and classified. Collaterals were classified into three different groups: marginal anastomoses (via the marginal = pericolic artery), intermediate mesocolic anastomoses (parallel to the marginal artery but neither adjacent to the IMV nor close to the duodenum) and central mesocolic anastomoses (next to the IMV at the level of the duodenojejunal junction and the lower border of the pancreas). RESULTS: All patients had a marginal anastomosis. However, the marginal anastomosis, as the only anastomosis between the superior and inferior mesenteric arteries at the splenic flexure, was observed in 41 cases (38%). In addition to the marginal artery, intermediate mesocolic anastomoses were found in 49 (46%) and a central mesocolic anastomosis was observed in 17 (16%) of the 107 cases in the splenic flexure mesocolon. It is in this latter variant that collateral vessels can be compromised during ligation/transection of the IMV. CONCLUSION: This new classification can contribute to a precise mesocolic dissection technique and splenic flexure mobilization and help prevent ischaemic damage to the descending colon.

Measurement of interscalene space volume in diagnosis of thoracic outlet syndrome: a cadaver study

Background/aim: The aim of this study was to measure the volume of interscalene space in thoracic outlet region on cadavers and radiological images and to analyze the potential value of these measurements in diagnosis and treatment of thoracic outlet syndrome (TOS). Materials and methods: The dimensions of the anterior interscalene space in 8 formalin-fixed human cadavers were studied by direct measurement and additionally evaluation of the volume of this space were done by using mold and volume calculation formula of square pyramid, due to resembling a pyramid. In the second phase of this study, interscalene space volume was calculated by formula and compared to calculations from computed tomography (CT) sections in 18 TOS and 16 control patients. Results: There was a strong correlation between the volume calculated by formula (4.79 ± 2.18 cm3) and by mold (4.84 ± 1.58 cm3), (R = 0.934, p = 0.001) in cadavers. The average volume measured in TOS patients (2.05 ± 0.32 cm3) was significantly smaller than control patients (4.30 ± 1.85 cm3, p < 0.0001). There were excellent or good results in 14 patients whereas in 4 patients who had neurogenic TOS achieved fair results after surgery. In these 4 patients the average volumes of abnormal sides were close to the healthy sides. Conclusion: In our study, volume of interscalene space in TOS patients was statistically smaller than control group. Also, the volume was even smaller in patients with excellent or good results after surgery. In this respect, volumetric measurements from CT sections could be used in diagnosis and treatment selection in TOS patients.

Intranasal Extramucosal Access: A New Access for Lateral Osteotomy in Open Rhinoplasty.

BACKGROUND AND OBJECTIVE: Different accesses have been used to perform lateral osteotomies in rhinoplasty. All of them have some disadvantages. The aim of this paper was to report a new access to overcome drawbacks of the other techniques in lateral osteotomy during open rhinoplasty. METHODS: An anatomical study was designed to search possibility of intranasal extramucosal access (open sky access) for the lateral osteotomy in open rhinoplasty. It was performed directly on the lateral wall of piriform aperture, and then possible advantages of this technique were investigated. Five fixed cadavers were used for this purpose. No drawbacks were observed during procedure in cadavers. Then the same procedure was performed in 23 consecutive rhinoplasty patients. Nineteen operations were primary and 4 operations were secondary. Median oblique osteotomies were added to the procedure in all patients. The mean follow-up was 17 months. RESULTS: Intranasal extramucosal access during lateral osteotomy was easily performed in all patients. Hemorrhage due to angular vessel injury was not occurred during intraoperative period. Edema and ecchymosis was minimal. Intranasal examination did not show any sign for nasal mucosal tearing in all patients. Residual bone spurs or bone irregularities were not observed in any patients. CONCLUSION: Intranasal extramucosal access that produces precise, predictable, and reproducible aesthetic and functional results could also provide better exposure during lateral osteotomy. Additionally, open sky access minimizes scars because it does not need additional incisions on the skin and mucosa. Protection of the internal periosteum of the nasal bones may be the main advantages of this technique.

Surgical anatomy of facial nerve for revision transmastoid surgery.

We analyze the relationships of the 3 segments of the facial nerve with respect to constant anatomic structures that can be identified during revision surgery via translabyrinthine approach. This study was conducted on 15 formalin-fixed cadavers whose facial nerves were dissected bilaterally under operative microscope via translabyrinthine approach. The distances between the round window niche and the midpoint of the tympanic segment and the beginning of the mastoid segment were 6.64 ± 1.79 mm and 3.99 ± 0.79 mm, respectively. The distances between the tympanic ostium of the eustachian tube and the first and the second genu were 7.02 ± 0.62 mm and 12.25 ± 1.24 mm, respectively. We used the superior semicircular canal, the tympanic ostium of the eustachian tube, and the round window niche as landmarks to identify the facial nerve during revision surgery. Our study also showed that the auricular branch may also be originated from the posterior surface of the facial nerve.

Measurements for the direct approach to the oval foramen to apply mandibular nerve blockade.

PURPOSE: The lack of certain quotable landmarks and not taking the morphometric variations into consideration for mandibular nerve blockade can cause some complications. The aim of this study was to ensure there are data for more feasible and successful lateral extraoral approach to block the mandibular nerve by proposing reliable and quotable landmarks. METHODS: The current study was carried out on 55 skulls at the anatomy departments of the Universities of Mersin and Ankara. The length of the zygomatic arch, measurements indicating the puncture point (PP), injection depth, and injection angle were revealed. The differences between sides and the relationships between the parameters were evaluated by using paired t-test and Pearson correlation test, respectively. RESULTS: Of all skulls, it is observed that the injection line passed anterior to the articular surface of the temporomandibular joint. The distance between external acoustic opening and PP showed positive correlation with the distance between oval foramen and the midpoint of the zygomatic arch on the left side (r = 0.364, P = 0.001). On the right, the correlation was close to the statistically significant level (r = 0.280, P = 0.072). The distance between external acoustic opening and PP that can be adapted to the living subjects was found as 26.31 ± 1.95 mm. Injection angle to the coronal plane was measured to be 16.39 ± 2.96 degrees. The difference between sides for this parameter was not statistically significant. CONCLUSIONS: The determined parameters are suggested to be convenient and quotable to help in successful direct application under three-dimensional computed tomography or computed tomography-fluoroscopy for blocking the mandibular nerve.

Motor nerve lengths of twenty-seven muscles in upper extremity.

The purpose of this study is to determine the lengths of motor nerves in the upper extremity. Motor nerves of 27 muscles in 10 cadavers (16 extremities) were dissected from their roots at the level of intervertebral foramen to the entry point of the nerves to the corresponding muscles. Distance between acromion and the lateral epicondyle of the humerus was also measured in all cadavers. Nerve length of the coracobrachialis muscle was the shortest (18.26 ± 1.64 cm), while the longest was the nerve of the extensor indicis (59.51 ± 4.80 cm). The biceps brachii, the extensor digitorum communis, and the brachialis muscles showed highest coefficient of variation that makes these nerve lengths of muscles inconsistent about their lengths. This study also offers quotients using division of the lengths of each nerve to acromion-the lateral epicondyle distance. Knowledge of the nerve lengths in the upper extremity may provide a better understanding the reinnervation sequence and the recovery time in the multilevel injuries such as brachial plexus lesions. Quotients may be used to estimate average lengths of nerves of upper extremity in infants and children. Moreover, reliability of the biceps brachii as a determinant factor for surgery in obstetrical brachial plexus lesions should be reconsidered due to its highest variation coefficient.

Anatomic relationship between the anterior sylvian point and the pars triangularis.

The aim of this study was to show morphological sulcal variations of the pars triangularis of the inferior frontal gyrus and to provide a clearer description of the anterior sylvian point. Thirty-six hemispheres of 18 adult cadavers were studied. The hemispheres were harvested by the classical autopsy method and fixed in 10% formalin solution for three weeks. In six hemispheres, the arteries and veins were filled with colored silicone. The proximal and distal segments of the sylvian fissure, the perpendicular distance of both the anterior sylvian point and inferior rolandic point to the insular cortex and the distances between the anterior ascending ramus and the precentral, central, and postcentral sulcus were measured. The anterior horizontal and ascending rami were exposed. The sulcus located on the pars triangularis was appraised. The relationship between the anterior sylvian point and the vascular structure around the sylvian fissure was examined. The rising of the anterior horizontal and ascending ramus from the sylvian fissure defines the shape of the pars triangularis. The pars triangularis has three shapes: V, U, and Y. In V- and Y-shaped pars triangularis both rami merge but in U-shaped pars triangularis the rami do not merge. The pars triangularis was Y-shaped in 30.76% (4/13) of the right hemispheres and in 50% (7/14) of the left hemispheres; U-shaped in 20.3% (3/13) of the right hemispheres and in 35.71% (5/14) of the left hemispheres; V-shaped in 40.61% (6/13) of the right hemispheres and in 14.29% (2/14) of the left hemispheres. Minimally invasive procedures use basic anatomic landmarks intracranially to reach the targeted area; therefore, exact and detailed knowledge of the anatomy of the sylvian fissure and pars triangularis is of great importance.

Nerve root to lumbar disc relationships at the intervertebral foramen from a surgical viewpoint: An anatomical study.

The objective of this study was to analyze relationship of the intervertebral disc to the nerve root in the intervertebral foramen. Fourteen formalin-fixed cadavers were studied and measurements were performed. At the medial line of the neural foramen, the disc-root distance gradually increased from L1-L2 to L5-S1. The shortest distance between the disc to nerve root was L1-L2 (mean, 8.2 mm) and the greatest distance was found at L3-L4 (mean, 10.5 mm). In the mid-foramen, the disc-root distance decreased from L1-2 to L5-S1. The shortest distance from the disc to nerve root was found at L5-S1 (mean, 0.4 mm); and the greatest distance, at L1-L2 (mean, 3.8 mm). For the lateral line, the distance between an intersection point between the medial edge of the nerve root and the superior edge of the disc and lateral line of the foramen consistently increased from L1-L2 to L5-S1. The shortest distance from nerve root to the lateral border of the foramen, at the point where the nerve root crosses disc was at level L1-L2 (mean, 2.6 mm), the greatest distance, L5-S1 (mean, 8.8 mm). The width of the foramina progressively increased in a craniocaudal direction (mean, 8.3-17.8 mm from L1-2 to L5-S1, respectively). The mean height of the foramina was more or less the same for disc levels (range, 19.3-21.5). The results showed that nerve roots at lower levels traveled closer to the midline of the foramen. This morphometric information may be helpful in minimizing the incidence of injury to the lumbar nerve root during foraminal and extraforaminal approaches.

Treatment of hyperdynamic nasal tip ptosis in open rhinoplasty: using the anatomic relationship between the depressor septi nasi muscle and the dermocartilaginous ligament.

BACKGROUND: Smiling causes a deformity in some rhinoplasty patients that includes drooping of the nasal tip, elevation and shortening of the upper lip, and increased maxillary gingival show. The depressor septi muscle leads this deformity. The dermocartilaginous ligament originates from the fascia of the upper third of the nose and extends down to the medial crus, merging into the depressor septi muscle. METHODS: In this study, 100 primary rhinoplasty patients were studied for hyperdynamic nasal tip ptosis. Of these patients, 36 had hyperdynamic nasal tip ptosis due to hyperactive depressor septi nasi muscle. The dermocartilaginous ligament was used as a guide to reach the depressor septi muscle in open rhinoplasty. Muscle excision was performed just below the footplates of the medial crura. A strong columellar strut graft was placed between the medial crura to avoid narrowing of the columellar width resulting from tissue excision and to withstand activation of depressor septi muscle remnants. RESULTS: No complications such as infection or hematoma occurred in the early postoperative period. The technique corrected the hyperdynamic nasal tip ptosis, increased upper lip length, and decreased gingival show when patients smiled. There was no narrowing of the columellar width. No depression in the columellar-labial junction due to distal resection of the depressor septi muscle was observed. CONCLUSION: The dermocartilaginous ligament can be used as a reliable guide to reach the depressor septi muscle in open rhinoplasty. Therefore, the hyperactive depressor septi muscle can be definitively identified and treated without an intraoral approach. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors at www.springer.com/00266.

Lumbosacral intrathecal nerve roots: an anatomical study.

BACKGROUND: The lumbosacral intrathecal anatomy is complex because of the density of nerve roots in the cauda equina. Space-occupying lesions, including disc herniation, trauma and tumor, within the spinal canal may compromise the nerve roots, causing severe clinical syndromes. The goal of this study is to provide spinal surgeons with a detailed anatomical description of the intrathecal nerve roots and to emphasize their clinical importance. METHOD: Ten formalin-fixed male cadavers were studied. They were dissected with the aid of a surgical microscope, and measurements were performed. RESULTS: The number of dorsal and ventral roots ranged from one to three. The average diameter of roots increased from L1 to S1 (0.80 mm for L1 and 4.16 for S1), respectively. Then their diameter decreased from S1 to S5 (4.16 mm for S1, 0.46 mm for S5). The largest diameter was found at S1 and the smallest at S5. The average number of rootlets per nerve root increased from L1 to S1, then decreased (3.25 for L1, 12.6 for S1, and 1.2 for S5), respectively. The greatest rootlet number was seen at S1, and the fewest were observed at S5. The average diameter of the lateral recess gradually decreased from L1 to L4 (9.1 mm for L1; 5.96 mm for L4) and then increased at L5 level (6.06 mm); however, the diameter of the nerve root increased from L1 to L5. The midpoint of distance between the superior and inferior edge of the intradural exit nerve root was 3.47 mm below the inferior edge of the superior articular process at the L1 level, while the origin of the L5 exit root was 5.75 mm above the inferior edge. The root origin gradually ascended from L1 to L5. CONCLUSIONS: The findings of this study may be valuable for understanding lesions compressing intradural nerve roots and may be useful for intradural spinal procedures.

Importance of the levator labii alaeque nasi muscle in dorsal septal deviations.

Deviated cartilages structures of the nose can be affected by nasal muscles, and deviation becomes conspicuous when the patient smiles. This condition depends on activity of nasal muscles, particularly the levator labii alaeque nasi muscle. A total of 124 septorhinoplasty operations were performed to correct dorsal concave septal deviation between 2005 and 2009 years. The 70 women and 54 men included in the study had an average age of 28 years. The average follow-up period was 12 months. Open septorhinoplasty was preferred in all cases. The medial part of the levator labii alaeque nasi muscle was extensively dissected from the lateral crus and surrounding tissues. The lateral crura of the alar cartilages were separated from the upper lateral cartilages in the scroll area. The dorsal septal deviation was corrected by combination of bilateral spreader grafts, which reinforced cartilage with horizontal control sutures. Early postoperative period was uneventful. Nasal obstruction was reduced after surgery, and significant subjective postoperative improvements were observed in all patients. Comparison of preoperative and postoperative photographs demonstrated improved dorsal nasal contour. Revision operation was performed in 3 cases. The corrected septal cartilage was in a good position in all revised cases; therefore, septal surgery was not performed in the revision operations. In conclusion, surgical disruption of the anatomic relationship between the muscle with the dorsal septal cartilage and reinforcement of the dorsal septal cartilage with spreader grafts and horizontal control sutures can decrease risk of recurrence.

Microsurgical anatomy for intraoperative preservation of the olfactory bulb and tract.

Damage to the olfactory bulb and tract is a frequently described complication of brain surgery in the frontal region, and it seems to be influenced by the surgical approaches. Eighty cerebral hemispheres and 5 formalin-fixed cadavers filled with colored latex were used. Parameters were directly measured, and after olfactory bulb and tract were mobilized with careful dissections, retraction of the frontal lobe was noted. The anterior border of the olfactory bulb is 22.21 (SD, 5.45) mm posterior to the frontomarginal sulcus, and arachnoidal dissection should be performed parallel to olfactory structures using sharp instruments to allow early visualization. Overall mobilization of the olfactory bulb and tract as 29.3 (SD, 6.4) mm in length is possible without disrupting the structures and enables a greater degree of the frontal-lobe elevation window up to 13.1 (SD, 3.2) mm. Using the morphometric data and anatomic knowledge may prevent unwanted anosmia complication during surgical approaches.

Perforating arteries of the anteromedial aspect of the thigh: an anatomical study regarding anteromedial thigh flap.

PURPOSE: Because the skin of anteromedial thigh region usually is thinner, pliable, hairless it can be preferred based on the requirements of the recipient site. In this way more information is necessary about the perforators of anteromedial thigh region. The aim of this cadaveric study was described to provide useful knowledge about localizations and number of anteromedial thigh perforators. METHODS: Study was carried out on 16 lower extremities of 9 cadavers. The area in anteromedial aspect of the thigh searched for perforators was defined between the anterolateral border of sartorius and the posterior border of gracilis. The diameters of the dissected perforators were measured and the locations were documented. RESULTS: A total of 204 perforators were dissected in 16 lower extremities. The majority of musculocutaneous perforators were from gracilis (24 of 37) and there were at most 3 musculocutaneous perforators arising from gracilis muscle. 167 septocutaneous perforators were identified. Origin of all perforators was determined as 52 from deep femoral artery, 25 from proximal part of femoral artery and 127 from distal part of femoral artery and their branches. Perforators with the largest diameter were the ones arising from the intermuscular septa between the adductor (longus and magnus) and sartorius muscles. The mean diameter of the perforators was 0.75 ± 0.11 mm and ranged between 0.61 and 0.96 mm. CONCLUSIONS: The septocutaneous perforators of the anteromedial aspect of the thigh are as much important as the musculocutaneous perforators and all they are with adequate to perform anteromedial thigh flap. This study provides numerical overview, useful perception about the localization of the perforators of the anteromedial aspect of the thigh and detailed anatomical basis for anteromedial thigh flap to be an important alternative.

Topographical anatomy of the dorsal branch of the ulnar nerve and artery: a cadaver study.

PURPOSE: The surgical anatomy of the dorsal branch of the ulnar nerve and artery on the dorsal aspect of the hand is important in design of neurocutaneous flaps for reconstructive surgery and serves as a donor site for nerve grafts. In this study, the course, location, and diameter of the dorsal branches of the ulnar nerve and artery were studied from anatomical and reconstructive perspectives. METHODS: Upper limbs of 14 (7 left and 7 right) and 22 formalin-preserved adult cadavers (15 left and 7 right) were dissected in two different centers. RESULTS: The diameters of the ulnar nerve, artery, and their dorsal branches were measured at selected reference points. The distances to specific anatomical landmarks were also measured, during their courses from the proximal forearm towards the middle phalanges of the 4th and 5th fingers. CONCLUSIONS: Our data may facilitate the design of neurocutaneous flaps nourished from the dorsal branches of the ulnar nerve and artery, and may aid in the harvesting of nerve grafts from the dorsal branch of the ulnar nerve, and provide a safe surgical approach to the dorsum of the hand.

Hidden unilateral agenesis of the frontal sinus: human cadaver study of a potential surgical pitfall.

PURPOSE: The aim of the study was to attract attention to the surgical significance of unilateral agenesis of the frontal sinus hidden by the overlapping expansion of the contralateral sinus toward the agenetic side. MATERIALS AND METHODS: Retrospective review of endoscopic transnasal sinus dissections of 55 human cadavers (42, formalin fixated; 13, fresh frozen) was done in a tertiary care academic medical center. Surgical and radiologic findings were noted. RESULTS: Absence of right frontal sinus ostium in the presence of a connection between the right and left frontal sinuses was demonstrated in 2 (3.6%) cadavers. An absent and an incomplete septum between the frontal sinuses were also noted in these cadavers. No accompanying abnormality of other sinuses was found, and no evidence of previous sinus surgery was noted in these 2 cadavers. CONCLUSIONS: If one of the frontal sinus ostia cannot be found during sinus surgery, although this sinus and its recess can be seen on the thick-sliced coronal computed tomographic (CT) scans, keep in mind that it may be (3.6%) an agenetic frontal sinus hidden by the extensive pneumatization of the contralateral sinus that is crossing the midline. It may not be possible to foresee this variant preoperatively by endoscopic examinations or thick-sliced CT scans. If there is suspicion, thin-sliced CT scans with reconstruction will be ideal to confirm the agenesis of the frontal sinus and to avoid complications. In the presence of such variant of frontal sinus, 1-sided successful frontal sinusotomy is adequate because this sinus or cell will already be drained through the treated frontal recess.

Single-stage posterolateral Corpectomy and circumferential stabilization without laminectomy in the upper thoracic spine: cadaveric study and report of three cases.

AIM: Surgical approach to the upper thoracic spine diseases is challenging since anterior interventions to this region are quite complicated with the presence of major vascular elements or important visceral and soft-tissue structures. MATERIAL AND METHODS: Operative technique was performed initially on eight cadavers and then on three consecutive patients. Costotransvesectomy was performed on the left side and pediculectomy were added on the contralateral side to achieve wide visual angle during corpectomy. A cage was implanted into the field of corpectomy from the left side and the stabilization procedure was completed with posterior instrumentation. RESULTS: Anterior low cervical approach is less invasive than posterior approach for T2 level and above.The area below T3 level includes the heart, aorta, common carotid or brachiocephalic artery and thoracic duct favoring the safety of posterior approach which provides a sufficient surgical window for corpectomy and circumferential stabilization at a single operation. CONCLUSION: The corpectomy procedure could be clearly performed under bilateral visualization of healthy bony margins with this technique. Although preserved laminae and spinous process lose the connection to the involved segment and hanged to adjacent levels only with posterior ligamentous complex, we propose that a chance of interlaminar fusion could further contribute to spinal stabilization rather than posterior instrumentation only.

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.

Fresh-frozen vs. embalmed bone: is it possible to use formalin-fixed human bone for biomechanical experiments on implants?

PURPOSE: As formalin is an extremely reactive electrophilic chemical that reacts with tissues, the purpose of this study was to explore whether formalin fixation could potentially alter the mechanical properties of bone tissue and have an effect on the primary stability measurements of implants. MATERIAL AND METHODS: Ø 3.3 x 8 mm, Ø 4.1 x 8 mm, and Ø 4.8 x 8 mm implants were placed on sockets prepared into the anterior surface of the radius of two fresh-frozen human cadavers. The insertion torque of each implant was quantified using a strain-gauged torque-wrench connected to a data acquisition system at a sample rate of 10 KHz, and resonance frequency analysis measurements were also undertaken for each implant. The cadavers were then subjected to embalment with 10% formalin for 3 months, and the same experiments were undertaken on the contra lateral radius of the cadavers. RESULTS: The insertion torques before and after chemical fixation were similar for Ø 3.3 mm (P>0.05), and higher values were obtained for Ø 4.1 mm and Ø 4.8 mm implants after chemical fixation (P<0.05). The resonance frequency analysis values before and after chemical fixation were similar for all implants (P>0.05). CONCLUSIONS: Implants have higher insertion torque values in formalin-fixed bone than fresh-frozen human bone, but similar implant stability quotients in both cases. The insertion torque technique can detect the difference between formalin-fixed and fresh-frozen human bone, but resonance frequency analysis cannot.