The vascular basis of the hemi-hamate osteochondral free flap. Part 1: vascular anatomy and clinical correlation

Purpose

The treatment of comminuted fractures of the proximal interphalangeal joint is highly challenging due to the complexities of joint bio-mechanics and stability. The hemi-hamate osteochondral auto-graft has been popularised in this role, able to replace articular loss and restore joint stability. Recent evaluation of their long-term follow-up however has shown the early development of osteoarthritis and potential early cartilage loss, which may be due to the non-vascularised nature of the graft. We offer a new technique that maintains vascularisation of the transferred hamate fragment, and investigate the anatomical vascular basis for the technique.

Methods

Dissection and angiographic studies of ten cadaveric specimens were undertaken, exploring the vascular anatomy of the dorsal hamate. A clinical case of hemi-hamate osteochondral free flap is presented, including preoperative, intraoperative and postoperative investigation of the relevant vasculature.

Results

Cadaveric studies demonstrated dorsal vascular supply to the hamate from the central of three dorsal carpal arches. The arch was supplied by the dorsal branch of the ulnar artery. Multiple supracapsular veins are present for use in flap venous drainage. This vascular pattern was found to be constant. A clinical case of hemi-hamate osteochondral free flap harvest demonstrated the same vascular anatomy intraoperatively. The digital artery was used as a recipient for microvascular anastomosis. Postoperative computed tomographic angiography and nuclear bone scan confirmed flap perfusion.

Conclusions

The hemi-hamate osteochondral flap has a reliable anatomical vascular basis, and is clinically feasible as a technique for early vascularisation of the osteochondral fragment to sustain the transferred articular cartilage.     

A unilateral septal flap based on the anterior ethmoidal artery (Castelnuovo’s flap): CT cadaver study

Objective

We describe our experience for repair septal perforation with a septal flap and we analyse the route of the septal branch of the anterior ethmoidal artery (AEA) in the septum area with a radiological anatomy study in order to perform this flap.

Study design

We carry out a prospective analysis with computed tomography scan in the cadaver heads and we perform an endoscopic technique in the patients.

Methods

Ten nasal cavities were analysed in five adult cadaveric heads and two patients diagnosed with anterior septal perforation were surgically treated. Measurements in the cadaveric heads were obtained from a sagittal plane of the nasal septum. The anterior point corresponds to the projection of the anterior insertion of the middle turbinate in the frontal process of the maxilla over the nasal septum. The posterior point was obtained with a vertical line passing through the entrance of the AEA in the nasal septum.

Results

The mean distance between the anterior point and the posterior point was 7.35 mm with a standard deviation of 0.95 mm. The lowest value was 5.5 mm and the highest value was 8.7 mm. We observed good epithelialisation and closure of the perforation in all patients.

Conclusion

The unilateral septal flap pedicle by anterior ethmoidal artery may be used for small and medium perforations with a pedicle smaller than 1 cm posterior to the axilla.

     

The posterior pedicled inferior turbinate–nasoseptal flap: a potential combined flap for skull base reconstruction

Objectives

To develop a combined pedicled flap comprising the mucoperiosteum and mucoperichondrium of the inferior turbinate, lateral nasal wall, nasal floor, and nasal septum based on the posterior lateral nasal artery, a branch of the sphenopalatine artery, for the reconstruction of skull base defects resulting from endoscopic expanded endonasal approaches.

Methods

Eleven fresh adult cadaver heads were dissected. Arterial distribution patterns of the inferior turbinate, lateral nasal wall, nasal floor, and nasal septum were investigated. The posterior pedicled inferior turbinate–nasoseptal flap was designed, measured, and harvested, and its ability to cover ventral skull base defects was examined.

Results

The inferior turbinate artery and/or posterior lateral nasal artery had 3.19 ± 1.47 (range 2–7) branches [mean outer diameter of largest branch, 0.40 ± 0.10 (range 0.24–0.60) mm] that anastomosed with the nasoseptal artery. These anastomosing arteries allowed the posterior lateral nasal artery to supply arterial blood to the nasoseptal mucoperichondrium and mucoperiosteum. Mean flap length was 100.65 ± 5.61 (range 91.43–109.44) mm, and minimum and maximum widths were 25.21 ± 2.29 (range 22.36–30.23) and 44.53 ± 5.02 (range 36.45–54.10) mm, respectively. Mean flap area was 3090.69 ± 288.08 (range 2612.97–3880.09) mm². The flap covered defects extending from the frontal sinus to the foramen magnum in all specimens.

Conclusions

Harvesting of a posterior pedicled inferior turbinate–nasoseptal flap is feasible. It should be considered a useful option for the reconstruction of large defects involving the anterior skull base, planum sphenoidale, sella turcica, and/or clivus.

     

The little finger ulnar palmar digital artery perforator flap: anatomical basis

Purpose

The aim of this study was to explore the cutaneous vascularization of the hypothenar region and investigate the anatomical basis for perforator propeller flaps for coverage of the flexor aspect of the little finger.

Methods

The area between the pisiform and the base of the little finger was studied in 14 hands of fresh cadavers injected with red latex. An oval flap 1.5 cm large was raised along the axis between these two points. Perforators going into the flap were dissected up to their origin from the ulnar palmar digital artery of the little finger, and their distance from the proximal edge of the A1 pulley was recorded.

Results

The mean number of perforator arteries entering the flap was 5.8 (range 4–8). A constant sizeable perforator was identified within 0.7 cm from the proximal margin of the A1 pulley in all 14 specimens. In the majority of cases (64 %), the most distal perforator was located at this level. Dissection of the flap was carried out suprafascially on the most distal perforator and 180° rotation allowed the flap to reach the flexor surface of the fifth finger. The donor site was closed primarily.

Conclusion

Distal perforators of the ulnar palmar digital artery of the little finger are constantly found. Our anatomical findings support the possibility of raising a propeller perforator flap from the hypothenar region for coverage of the flexor aspect of the little finger. Its clinical application could provide a quick and straightforward single-stage option with a negligible donor-site morbidity for reconstruction of such defects.     

An anatomic study of the dorsal forearm perforator flaps

Purpose

The posterior forearm is an excellent donor site for the vascular pedicled cutaneous flaps; yet, there is surprisingly little detailed anatomical information based on clinical decision making. This study was undertaken to evaluate the anatomical basis of the dorsal forearm perforator flaps and to provide anatomical landmarks to facilitate flap elevation.

Methods

Thirty cadavers were available to perform this anatomical study after arterial injection. Twenty fresh cadavers were injected with a modified lead oxide–gelatin mixture, selected for 3-dimensional reconstruction using special software (MIMICS) and the arterial territory measured with Scion Image. Other ten were injected with red latex preparation, and perforators were identified through dissection.

Results

(1) The average number of posterior interosseous artery cutaneous perforators in the dorsal forearm was 5 ± 2, the average diameter was (0.5 ± 0.1) mm, and the pedicle length was (2.5 ± 0.2) cm. The average cutaneous vascular territory was (22 ± 15) cm². Cutaneous perforators could be found along the line extending from the lateral epicondyle to the radial border of the head of ulna. (2) Dorsal branch of anterior interosseous artery supplied blood to distal third of dorsal forearm; its average diameter was 0.8 mm.

Conclusion

The free transplantation of the posterior interosseous perforator artery flaps or rotary flap pedicled by dorsal branch of anterior interosseous artery for defect reconstruction is feasible.     

Split temporalis muscle flap anatomy, vascularization and clinical applications

Introduction

For more than a century, the temporalis muscle has been used for facial reconstructions. More recently, a split temporalis muscle flap elevated on the superficial temporal pedicle has been described, for which the resulting gain of length makes crossing of the midline possible, as well as reconstruction of substance losses exceeding the midline.

Materials and methods

Fourteen fresh cadaveric dissections were performed to study the different techniques for splitting the temporalis muscle. Dissections with catheterization and injection of radio-opaque contrasting agent in the external carotid artery were then performed to specify the vascularization of the flap split on the superficial temporal pedicle.

Results

The duplication of the superficial temporal pedicle grants greater length compared to that of the deep pedicles, 57 mm versus 40 (p = 0.036). The middle temporal artery is capable of ensuring the vascularization, and therefore the viability, of the split flap. From these results, we spoke about the limitations of this study and we have inferred the main indications.     

A simple pre-operative imaging method to assess donor and recipient anatomy in hemi-hamate arthroplasty for proximal interphalangeal joint reconstruction

Purpose

Post-traumatic arthritis is common in long-term follow-up of patients undergoing hemi-hamate arthroplasty (HHA). We hypothesize that anatomic mismatch could play a role in the development of arthritis. The purpose of this study is to establish a novel, computed tomography (CT)-based imaging technique for pre-operative assessment in HHA. With this technique, our group aims to identify digits with a high likelihood for anatomical mismatch between the donor graft and recipient interphalangeal joint. Using this technique to eliminate cases with high-likelihood of incongruent anatomy, we hypothesize the rates of arthritis could be reduced.

Methods

We conducted a retrospective review of upper extremity CT scans from 2007 to 2014 at our institution. Those studies meeting our inclusion criteria were exported to a clinical radiology software suite. Subsequently, angular and linear measurements of the hamate and potential recipient proximal interphalangeal joints were collected. Angular and linear comparisons were then made between the donor hamate graft and the individual recipient sites. Using pre-established cutoff values, matches were deemed to be inconsistent or consistent.

Results

The study included 31 CT scans. The rate of anatomical consistency was low; the small finger was most often consistent (38.7 %) and the index finger was least often consistent (12.9 %). Linear inconsistency was common in all joints besides the small finger; angular inconsistency was most prevalent in the index and long fingers.

Conclusions

This novel use of CT scans as a tool for pre-operative HHA planning is a crucial first step in trying to reduce the observed rates of arthritis after HHA.

     

Three-dimensional templating arthroplasty of the humeral head

Background

No anatomical study has been conducted over Asian population to design humeral head prosthesis for the population concerned. This study was done to evaluate the accuracy of commercially available humeral head prosthetic designs, in replicating the humeral head anatomy.

Methods

CT scan data of 48 patients were taken and their 3D CAD models were generated. Then, humeral head prosthetic design of a BF shoulder system produced by a standardized, commercially available company (Zimmer) was used for templating shoulder arthroplasty and the humeral head size having the perfect fit was assessed. These data were compared with the available data in the literature.

Results

All the humeral heads were perfectly matched by one of the sizes available. The average head size was 48.5 mm and the average head thickness was 23.5 mm. The results matched reasonably well with the available data in the literature.

Conclusions

The humeral head anatomy can be recreated reasonably well by the commercially available humeral head prosthetic designs and sizes. Their dimensions are similar to that of the published literature.     

Acquisition of thin coronal sectional dataset of cadaveric liver

Purpose

To obtain the thin coronal sectional anatomic dataset of the liver by using digital freezing milling technique.

Methods

The upper abdomen of one Chinese adult cadaver was selected as the specimen. After CT and MRI examinations verification of absent liver lesions, the specimen was embedded with gelatin in stand erect position and frozen under profound hypothermia, and the specimen was then serially sectioned from anterior to posterior layer by layer with digital milling machine in the freezing chamber. The sequential images were captured by means of a digital camera and the dataset was imported to imaging workstation.

Results

The thin serial section of the liver added up to 699 layers with each layer being 0.2 mm in thickness. The shape, location, structure, intrahepatic vessels and adjacent structures of the liver was displayed clearly on each layer of the coronal sectional slice. CT and MR images through the body were obtained at 1.0 and 3.0 mm intervals, respectively.

Conclusion

The methodology reported here is an adaptation of the milling methods previously described, which is a new data acquisition method for sectional anatomy. The thin coronal sectional anatomic dataset of the liver obtained by this technique is of high precision and good quality.     

Medial calcar of proximal humeral fracture as landmark in restoration of humeral length in case of hemiarthroplasty

Purpose

Several methods to restore the appropriate length of the humerus in the case of proximal humeral fractures treated by hemiarthroplasty have been previously published. Our study evaluates the possibility of using the medial calcar of humerus for humeral length reconstruction not based on preoperative planning.

Methods

Preparations of 320 dry humeral bones were used for the purpose of the study. Points of interest were marked on each bone: the most proximal point of the humeral head, the crest of greater tuberosity, diameters of the head, the anatomical and surgical necks. Proximal parts of bones were then scanned from two angles with a digital camera and all measurements were performed on calibrated photographs. We compared accuracy in humeral length reconstruction using insertion of the pectoralis major and the area of medial calcar where usually a fracture develops.

Results

The distance between the top part of the humeral head and the insertion of pectoralis major was 54.1 ± 6.0 mm. The distance between the lateral margin of the anatomical neck and the medial calcar was 51.4 ± 4.3 mm. We compared these data with diameters of the humeral head.

Conclusions

The site of the fracture can be used for the reconstruction of the humeral length with greater accuracy than area of the pectoralis major insertion. We suggest that to obtain the final distance between the lateral margin of the artificial head and medial calcar of the fracture 2–3 mm should be added to the diameter of the head.     

Analysis of the position of the branches of the ulnar nerve in Guyon’s canal using high-resolution MRI in positions adopted by cyclists

Purpose

To study variations in the anatomical relationships of the branches of the ulnar nerve in Guyon’s canal relative to the hamulus of hamate (HH) in a grip encountered among cyclists.

Materials and methods

Forty-seven wrist examinations were performed on a 3-T MRI (soft antenna, 16 channels) in propeller sequence in the plane perpendicular to the carpus in 28 healthy volunteers in three cycling positions (neutral, hyperextension and ulnar deviation). The positions and distance between the superficial (SB) and deep (DB) branches of the ulnar nerve with respect to the HH were determined on the section passing through the HH.

Results

The mean distances between the SB (d _s) and DP (d _p) and HH were 2.4 and 0.6 mm, respectively. The d _s in hyperextension and ulnar deviation were 2.2 mm (P = 0.3) and 3 mm (P = 0.07), respectively. The d _p in hyperextension and ulnar deviation were 0.3 mm (P = 0.02) and 0.5 mm (P = 0.15), respectively. Hyperextended, 60 % of SB and 40 % of DB were close to the HH, and 26 % of DB came directly in contact with it. In ulnar deviation, 30 % of SB and 29 % of DB approached HH, and 47 % of DB were in contact with it.

Conclusion

This study shows that SB and DB positions of the ulnar nerve vary with respect to the HH depending on the position of the wrist, and such differences may promote Guyon’s canal syndrome in cyclists.

     

The superomedial bare area of the costal scapula surface: a possible cause of snapping scapula syndrome

Purpose

Scapulothoracic bursitis is a painful condition of the scapulothoracic articulation, which may be caused by various pathological anatomical associations. We have arthroscopically observed a constant bare area of bone on the costal scapula surface in patients with scapulothoracic bursitis, contradictory to traditional anatomical reports of scapular muscle relations. We undertook a cadaveric study to further define this anatomical feature.

Methods

Twelve cadaveric shoulders were dissected. The costal surface of the scapula was systematically examined for the presence of a superomedial bare area in each shoulder by three independent clinicians, with dimensions measured using digital calipers.

Results

In all shoulders, there was a clearly defined bare area of bone on the superomedial aspect of the costal surface of the scapula between the serratus anterior insertion and subscapularis origin. The bare area was typically crescenteric in shape, with variable length (mean 22.3 ± 6.0 mm) and width (10.8 ± 2.8 mm). The bare area length (p = 0.043) and width (p = 0.033) were significantly greater in female shoulders compared to male shoulders.

Conclusions

We have established the presence of the superomedial bare area of the costal scapula surface. With an absence of overlying subscapularis muscle, this bare area carries the potential for scapulothoracic impingement, and should be considered as a possible aetiological factor in all patients presenting with scapulothoracic bursitis.     

Redefining the proximal ulna anatomy

Purpose

Complex fractures of the olecranon have always been a difficult condition for treatment. Successful reconstruction depends on restoration of the anatomic contributors to stability. The purpose of this study was to define the proximal ulna anatomy in detail with respect to fracture fixation and arthroscopy.

Methods

In 50 normal adult ulnae (26 left, 24 right); posterior olecranon height (POH), olecranon width (OW), trochlear notch width (TW), the distances between the olecranon and the trochlear notch on radial and ulnar sides (RTH, UTH), and proximal ulnar angulations were measured with a ruler and a digital goniometer.

Results

The average POH was 24.6 mm, OW was 23.1 mm, TW was 22.3 mm, RTH was 16.2 mm, and UTH was 15.8 mm. The mean value for proximal ulna torsion angle (PUTA) was found 11.1°. The mean varus angulation was 9.3°. The average articular angle was 27.7° and proximal ulnar dorsal angulation (PUDA) was 8°.

Conclusions

The unique bony architecture of the proximal ulna presents particular difficulties for the implants used in fracture fixation and arthroplasty of the elbow. Knowing the detailed anatomy of the variations of proximal ulna will guide the surgeon to obtain a more reliable length of the olecranon and to offer a safe place for Kirschner wire replacement concerning humero-ulnar joint functionality. In this study, PUTA was also defined. The angle determines the rotation of the proximal ulna and it has a great importance for the movements of the joint. The measured angulations will help the surgeon to design the proper prosthesis for the maintenance of the functions of the elbow joint.     

Novel patterns for the growing main bronchi in the human fetus: an anatomical, digital and statistical study

Purpose

Intensive progress in prenatal medicine results in performing airway management in the fetus affected by life-threatening congenital malformations. This study aimed to examine age-specific reference intervals and growth dynamics for length, proximal and distal external transverse diameters, and projection surface areas of the two main bronchi at varying gestational ages, including their relative growth in length and projection surface area.

Materials and methods

Using anatomical dissection, digital image analysis and statistics, length, proximal and distal external transverse diameters, and projection surface areas of the right and left main bronchi were examined in 73 human fetuses (39 males, 34 females) aged 14–25 weeks, derived from spontaneous abortions and stillbirths.

Results

Statistical analysis showed no sex differences. Between the 14 and 25th week of gestation, the lengths of the right and left main bronchi increased from 1.43 ± 0.18 to 3.18 ± 0.39 mm, and from 2.97 ± 0.16 to 7.58 ± 1.95 mm, in accordance with the functions: $ y = - 4.850 + 2.452 x \; \text{ln}\left( {\text{Age}} \right) \pm 0.400\;{\text{and}}\;y = - 15.005 + 7.093x \; \text{ln} \left( {\text{Age}} \right) \pm 0.579 $ , respectively. The proximal external transverse diameters of the right and left main bronchi varied from 2.13 ± 0.41 to 4.24 ± 0.20 mm, and from 1.84 ± 0.06 to 3.67 ± 0.66 mm, following the logarithmic models: $ y = - 8.666 + 4.018x \; \text{ln}{\rm (Age)} \pm 0.367\;{\text{and}}\;y = - 6.938 + 3.305x{\text{ ln(Age) }} \pm 0.323 $ , respectively. The distal external transverse diameter rose from 2.09 ± 0.47 to 4.24 ± 0.20 mm, as $ y = - 8.723 + 4.021x{\text{ ln(Age)}} \pm 0.392 $ for the right main bronchus, and from 1.85 ± 0.04 to 3.67 ± 0.66 mm, like $ y = - 6.924 + 3.280x{\text{ ln(Age)}} \pm 0.348 $ for the left one. On either side, there were no statistically significant differences between values of the proximal and distal transverse diameters of the main bronchus. The projection surface areas of the right and left main bronchi ranged from 2.95 ± 0.19 to 13.34 ± 2.12 mm², and from 5.57 ± 0.21 to 28.52 ± 5.24 mm², as $ y = - 10.212 + 0.943x{\text{ Age}} \pm 1.739 $ and $ y = - 19.119 + 1.875x{\text{ Age}} \pm 3.054 $ . The two main bronchi revealed a proportionate increase in both length and projection surface area, since the right-to-left bronchial length ratio and the right-to-left bronchial projection surface area ratio were stable, 0.41 ± 0.07 and 0.47 ± 0.08, respectively, throughout the analyzed period.

Conclusions

The main bronchi show no sex differences. The right and left main bronchi grow logarithmically in length and external transverse diameter, and linearly in projection surface area. The right and left main bronchi evolve proportionately, with the right-to-left bronchial ratios of 0.41 ± 0.07 for length, and 0.47 ± 0.08 for projection surface area.     

Morphometric study of mandibular foramen in macerated skulls to contribute to the development of sagittal split ramus osteotomy (SSRO) technique

Purpose

The aim of this study was to provide morphometric data, obtained from macerated mandibles, which might facilitate the topographic location of the mandibular foramen, considering aspects such as gender, age and ethnicity.

Materials and methods

One hundred and eighty-five macerated mandibles of adult black and white individuals of both sexes were analyzed. Initially, 5 points were established: MF, the lowest point of the mandibular foramen; S, greatest concavity of the mandibular notch; A, anterior margin of the ramus of mandible; P, posterior margin of the ramus of mandible; and Go, gonion. Then the following measurements were performed bilaterally: MF-S, MF-A, MF-P and MF-Go.

Results

The following mean values were found: MF-S: 21.02 mm for white females (WF) and 22.00 mm for black females (BF); 24.40 mm for white males (WM) and 24.35 mm for black males (BM); MF-A: 17.05 mm for WF and 18.09 mm for BF; 17.18 mm for WM and 18.11 mm for BM; MF-P: 11.11 mm for WF and 12.24 mm for BF; 13.10 mm for WM and 14.15 mm for BM; MF-Go: 19.00 mm for WF and 19.44 mm for BF; 23.13 mm for WM and 22.12 mm for BM.

Conclusions

The values found in this study, considering gender, age and ethnic group, can be used as a parameter to carry out the sagittal split ramus osteotomy technique, making it more predictable and with less risk of complications.     

Prevalence and variance of the sternalis muscle: a study in the Chinese population using multi-detector CT

Objective

To analyze the prevalence, anatomical features, as well as variance of the sternalis muscle in the Chinese population using multi-detector computed tomography (MDCT).

Methods

We retrospectively reviewed 6,000 adult axial MDCT images to determine the overall and gender prevalence of the sternalis muscles. We also analyzed the side prevalence and anatomical features, including shape, size, location and course.

Results

The sternalis muscle was present in 347 (5.8 %) of 6,000 adults. This muscle was more common in males (6.0 %, 187/3091) than in females (5.5 %, 160/2909). Among the 347 adults, 118 (34.0 %) had bilateral sternalis muscles; 148 (42.7 %) had right sternalis muscles; and 81 (23.3 %) had left sternalis muscles. The sternalis muscle was either flat or nodular and located superficial to the major pectoral muscles on CT axial transverse images. According to the muscle morphology and course, we classified sternalis muscles as three different types and nine subtypes. The muscles appeared with a single head and single belly in 58.5 %, double or multiple heads in 18.1 %, and double or multiple bellies in 23.4 %. The mean length, width and thickness were 111.1 ± 33.0, 17.7 ± 9.9 and 4.1 ± 1.7 mm measured on MDCT.

Conclusion

The sternalis muscle was highly prevalent in normal Chinese adults. MDCT is an effective method to demonstrate this muscle in vivo.     

A morphometric anatomical and comparative study of the foramen magnum region in a Greek population

Background

The foramen magnum (FM), a complex area in craniocervical surgery, poses a challenge for neurosurgeons. The knowledge of the detailed anatomy of the FM, occipital condyles (OC) and variations of the region is crucial for the safety of vital structures. This study focuses on the FM and OC morphometry, highlights anatomical variability and investigates correlations between the parameters studied.

Materials and methods

One hundred and forty-three Greek adult dry skulls were examined using a digital sliding calliper (accuracy, 0.01 mm).

Results

Mean FM width and length were found 30.31 ± 2.79 and 35.53 ± 3.06 mm, respectively. The commonest FM shape was two semicircles (25.9 %), whereas the most unusual was irregular (0.7 %). The OC minimum width, maximum width and length were 5.71 ± 1.61, 13.09 ± 1.99 and 25.60 ± 2.91 mm on the right, and 6.25 ± 1.76, 13.01 ± 1.98 and 25.60 ± 2.70 mm on the left side. The commonest OC shape was S-like and the most unusual was ring, bilaterally. The mean anterior and posterior intercondylar distances were 19.30 ± 3.25 and 51.61 ± 5.01 mm, respectively. The OC protruded into the FM in 86.7 % of the skulls. Variations such as a third OC existed in 5.6 % and basilar processes in 2.8 %. Posterior condylar foramina were present in 75.5 %. The gender was correlated with FM width and length, OC length, bilaterally, anterior intercondylar distance (AID) and posterior intercondylar distance (PID). The OC protrusion and existence of posterior condylar foramina were correlated. Bilateral asymmetry for OC shape was statistically significant.

Conclusion

Our results provide useful information that will enable effective and reliable surgical intervention in the FM region with the maximum safety and widest possible exposure.     

The effect of tumour necrosis factor-α and insulin on equine digital blood vessel function in vitro

Objective and design

Insulin and inflammatory cytokines may be involved in equine laminitis, which might be associated with digital vascular dysfunction. This study determined the effects of TNF-α and insulin on the endothelial-dependent relaxant responses of equine digital blood vessels and on equine digital vein endothelial cell (EDVEC) cGMP production.

Material

Isolated rings of equine digital arteries (EDAs) and veins (EDVs) were obtained and EDVECs were cultured from horses euthanized at an abattoir.

Methods

The effect of incubation with TNF-α (10 ng/ml) and/or insulin (1,000 μIU/ml) for 1.5 h or overnight under hyperoxic and hypoxic conditions on carbachol (endothelium-dependent) induced relaxation was assessed. The time course and concentration dependency of the effect of TNF-α and the effect of insulin (1,000 μIU/ml) on EDVEC cGMP production was determined.

Results

Incubation of EDAs overnight with TNF-α under hypoxic conditions resulted in endothelial-dependent vascular dysfunction. EDVs produced a more variable response. TNF-α increased EDVEC cGMP formation in a time- and concentration-dependent manner. Insulin had no significant effects.

Conclusions

There is a mismatch between the results obtained from isolated vessel rings and cultured endothelial cells suggesting TNF-α may reduce the biological effect of NO by reducing its bioavailability rather than its formation, leading to endothelial cell dysregulation.     

The prevalence, length and position of the anterior loop of the inferior alveolar nerve in Chinese, assessed by spiral computed tomography

Purpose

This study used spiral computed tomography to identify the anterior loop of the inferior alveolar nerve, and to measure its length and position in Chinese. This information may be useful to safely install endosseous implants in the most distal area of the interforaminal region.

Methods

Sixty-eight Chinese patients were included in this retrospective study. Patients were scanned by 64-slice spiral computed tomography, and the prevalence, length, and position of the anterior loop were assessed using the multiplanar capabilities of software.

Results

An anterior loop could be identified in 83.1 % of the cases, with a mean length of 2.09 mm (range 0–5.31 mm). The mean distance from the superior border of the mental foramen to the alveolar crest was 13.00 mm, and the mean distance from the superior border of the origin of the anterior loop to the alveolar crest was 17.83 mm.

Conclusions

The anterior loop was highly prevalent in Chinese, and the length of the anterior loop was highly variable. Therefore, we recommend that drilling commences from a location approximately 5.5 mm mesially from the mental foramen, when installing implants in the most distal interforaminal area.     

The human locus coeruleus 3-D stereotactic anatomy

Purpose

The main goal of this work was to study the stereotactic anatomy of the human locus coeruleus (LC), important relay of adrenergic and dopaminergic human brainstem (HB) circuitry, to allow its easy localization on MRI and in microsurgical procedures.

Methods

Forty LC were studied from 20 adult HB of both sexes. The melanin pigmentation of its cells was used to identify and localize them and so to define the 2-D and 3-D LC contours. These HB were cut on a cryomicrotome with 3-D referenciation. The slices were coloured with haematoxyline-eosin. On the slices, digitized images of the cells were referenced to the midline, the fourth ventricle floor plane and the pontomedullary junction plane with an appropriate computer program.

Results

The LC revealed to be a symmetric, thin and elongated nucleus, divergent caudally except in its superior part, with a sub-ependymal location on the superior dorsal lateral pons. The main LC dimensions are: length 12.0–17.0 mm (m 14.5); width 2.5 mm; height 2.0 mm. The 3-D references of the LC center are: 3.2 ± 0.3 mm to the midline; 1.1 ± 0.2 mm to the IV ventricle floor and 18.5 ± 1.5 mm to the ponto-medullary junction.

Conclusions

The human LC is a nucleus thinner and longer than previously described (in average 14.5 mm long and 2–2.5 mm thick), localized 1 mm under the IV ventricle, 3 mm apart from the midline and centered 14–21 mm above de ponto-medullary junction. No correlation was found between LC and pons dimensions, the gender or the age.