Rare anatomic variation on a 10,000-year-old South American skeleton: the case of Iuzu, Toca dos Coqueiros, Piauí State, Brazil.

PURPOSE: A skeleton named Iuzu has been unearthed from an exceptional middle Holocene burial in Toca dos Coqueiros site, in Serra da Capivara National Park (UNESCO World Heritage Site, Piauí State, Brazil). During a bioarchaeological analysis of its remains, we discovered that Iuzu was suffering from rare vertebral malformations. A double foramen transversaria, the agenesis of a foramen on the atlas and the hypoplasia of the transverse process of the axis have been highlighted. We aimed to deduce the clinical consequences of the malformation on the patient's health. METHODS: We proceeded to macroscopic observation and radiography of the bones, then we search for other examples of such a pathology in archaeological litterature. RESULT: The malformation caused vascular insufficiency that may have led to neurological lesions leading to various pains and troubles. The very rare malformations Iuzu presented have not been found on a paleoindian skeleton from South America so far. CONCLUSION: This case allowed us to examine the conditions of selection of individuals buried in southern Piauí during the Middle Holocene, during which time this rite does not seem to predominate.

Vascularization and morphological changes of the endplate after axial compression and distraction of the intervertebral disc.

STUDY DESIGN: An in vivo study of the rabbit's endplate and intervertebral disc (IVD). OBJECTIVE: To assess the histologic features and vascularization of the endplate after axial compression and distraction, along with the degeneration and regeneration status of IVD. SUMMARY OF BACKGROUND DATA: Current studies mainly focus on the changes in the IVD in response to degeneration and regeneration. However, the basic science regarding degenerative changes of the vertebral endplate and its actions on the IVD is lacking. The endplate is responsible for nutrient flow to the IVD through diffusion. It has been postulated that changes in the endplate may be responsible for the degeneration of the IVD. METHODS: Twenty New Zealand white rabbits were equally divided into 4 groups as follows; group A, 28 days of compression only; group B, 28 days of disc compression followed by 28 days of unloading; group C, 28 days of disc compression followed by 28 days of distraction; and group D, sham operated animals with apparatus placement only. At the end of the study, all the animals in the 4 groups were killed and the lumbar segments harvested for analysis of their disc height, vascularity, and histologic examination. RESULTS: Compression decreased the disc height and the rabbits showed signs of disc degeneration. Ossified endplates with decreased cells and extracellular matrix, and decreased vascular channel volume were observed. Cellular and morphologic regeneration were observed on unloading and distraction of the compressed discs, although the cartilaginous endplates were partially ossified. The volume of vascular channels increased significantly after distraction. Fluorescent vascular tracer showed the presence of active blood flow in the vascular channels near the cartilaginous endplates. CONCLUSION: Compression resulted in degeneration of the cartilaginous endplate and decrease in the osseous endplate vascular channel volume, both of which led to the degeneration of the IVD. Unloading and distraction allowed the regeneration of the extracellular matrix in both the endplate and the recovery of vascular channels.

Osseous and vascular anatomical variations within the C1-C2 complex: a radiographical study using computed tomography angiography.

BACKGROUND: One of the limiting factors of C1-C2 fixation is the location of the vertebral artery (VA). The authors sought to assess the potential variations in atlanto-axial VA anatomy using computed tomography angiography (CTA). METHODS: Detailed measurements were made on digital images of 106 patients undergoing CTA at our institution (54 males, 52 females; mean age 56, range 20-86). Distances, diameters and angles of osseous and vascular elements of the atlanto-axial complex were measured. RESULTS: Optimal C1 and C2 screw trajectories demonstrated wide variations among patients. The size of the VA groove or foramen was not predictive of exact arterial location or size. CONCLUSIONS: The size, location and path of the VA cannot be precisely predicted by the appearance of osseous structures such as the transverse foramina and/or the VA groove. CTA provides additional information regarding the atlanto-axial complex, and should be considered as a useful adjunct in the preoperative evaluation of select patients.

Anatomical evaluation of the groove for the vertebral artery in the axis vertebrae for atlanto-axial transarticular screw fixation technique.

Anatomical measurements were studied on 40 dry axis vertebrae to determine the suitability of the groove for the vertebral artery for atlanto-axial transarticular screw fixation technique. We measured 13 parameters including three angular and 10 linear dimensions related to the groove of the vertebral artery, pedicle, and pars interarticularis and evaluated 80 measurements for each parameter. All measurements were done after placing a Kischner guide wire through the pedicle. We found that differences between measurements on the left and right sides of each vertebra were nonsignificant. In spite of the variability in measurements such as height, width, and median angle of the pedicle, the decline angle for instrumentation, the depth of the groove for the vertebral artery, and the internal height of the pars interarticularis, all of these had good symmetry. However, there were statistically significant differences between the sides in measurements for both the width (P=0.05) and the angle (P<0.02) of the pedicle allowing instrumentation and they did not show good symmetry. The risk of vertebral artery injury was found to be 22.5% per specimen, or 16.25% per screw inserted because the internal height of the pars interarticularis at point of fixation was

Congenital anomalies of the odontoid process.

Anomalous development of the odontoid is uncommon, and its clinical significance lies in its potential for producing serious neurologic sequelae due to atlantoaxial instability. Although there are several recognized variations (aplasia, hypoplasia, and os odontoideum), clinically they share the same signs and symptoms, and the treatment is identical. Symptoms are usually due to instability of the atlantoaxial joint, with compression of the spinal cord and anteriorly against the axis or posteriorly from the ring of the atlas. Patients may present with no symptoms, with persistent neck complaints, with transient or permanent neurologic deficits, or with sudden death. Symptoms from cranial nerve irritation seldom occur, but occasionally symptoms of cerebral and brain stem ischemia are noted as a result of compression of the vertebral arteries in the area of the atlas. If the condition is suspected, the diagnosis usually can be confirmed on lateral flexion-extension roentgenograms. Special techniques are often required, particularly lateral laminagrams, and flexion-extension stress roentgenograms are necessary to determine the presence and degree of atlantoaxial instability. The role of prophylactic surgical stabilization is not yet established. If instability greater than 5 mm. is demonstrated or the patient has clinical findings of neurologic compromise, surgical fusion should be performed.

The arterial blood supply of the cervical vertebrae of the ox (bos taurus l.).

The arterial supply to the cervical vertebrae of the ox was studied in 22 animals (Friesland, Jersey and Guernsey cross-breeds), ranging from near full-term foetuses to adults. Various techniques, including angiography and clearing of bone, were employed to expose the extra- and intraosseous distribution of the arteries and a description is given of a modified Spalteholtz clearing technique. The extraosseous nutrient arteries are described and illustrated. A uniform pattern emerged from the investigation and it is suggested that the main branches be named: (1) the artery of the vertebral arch; (b) the artery of the transverse process; (c) the basivertebral arteries. Frequent anastomoses between epi- and metaphysial vessels in young animals are reported, and stress is laid on the effective collateral supply maintained by the extra- and intraosseous nutrient vessels.

[Arterial vascularization of the axis]. / La vascularisation arterielle de l'axis

The authors have studied the vascularization in the axis by microangiography of bone sections from 5 foetuses and 8 adults. All the arteries originate from the vertebralis : periosteal vessels arising from anterior and posterior intertransversary arteries, supply arteries originating in ventral and dorsal arteries. There are 2 distinctive arterial arches, one on the anterior face of the first two cervical vertebrae, the other on the posterior half of the vertebral corpus of the dens. Vascularization in the dens has particularly been studied. There are no anastomoses between the arteries of the dens and those of the axis corpus in foetuses. On the contrary, there are such anastomoses in adults. The least vascularized zone seem to be the neck of the dens.

Non-union of the odontoid process. An experimental investigation.

A clinical study of fractures of the odontoid process showed a 62 per cent failure on union. Of many features studied, only displacement and its direction had a definite bearing on non-union of the fracture. Blood supply was considered as a possible etiological factor. The blood supply of the human odontoid was elucidated by means of studying 19 human autopsies by means of microangiography. The dog was found to have a similar blood supply and hence, was used as the experimental model. Two osteotomies were performed; one below the accessory ligaments and one above the accessory ligaments. All osteotomies carried out below the accessory ligament united and all carried out above failed to unite. Microangiographic studies revealed however, that avascular necrosis was not the cause of non-union. Further anatomic studies revealed that different size gaps occurred depending on the level of the osteotomy, with a large gap occurring in the osteotomy of the odontoid which was performed above the accessory ligament. First the result of immobilization and the healing of the odontoid osteotomy was derived, by carrying out an instant occipito-cervical fusion by means of wire loops and methylmethacrylate. In distinction to the free floating apical segment of non-immobolized spines, with a high odontoid osteotomy, the occipito-cervical fusion resulted in a dense fibrous tissue stabilizing the apical fragment but at no time was bony union observed. A final attempt was to secure immobilization and reduce the gap, by carrying out only a partial osteotomy. The osteotomy was performed in such a way that the posterior cortex was left intact. Union occurred in all instances. The fracture gap and movement play a definite role in the pathogenesis of pseudarthrosis of the odontoid process. Where gap and movement were eliminated, union occurred. It is difficult to transpose this experimental situation to the clinical one, for the assessment of gap clinically, is only radiographic. This method is much too imprecise to be of value in this assessment. The fact however, that a high rate of non-union is associated with a high degree of displacement, supports the experimental thesis.