Vertebral pneumaticity is correlated with serial variation in vertebral shape in storks.

Birds and their ornithodiran ancestors are unique among vertebrates in exhibiting air-filled sinuses in their postcranial bones, a phenomenon called postcranial skeletal pneumaticity. The factors that account for serial and interspecific variation in postcranial skeletal pneumaticity are poorly understood, although body size, ecology, and bone biomechanics have all been implicated as influencing the extent to which pneumatizing epithelia invade the skeleton and induce bone resorption. Here, I use high-resolution computed-tomography to holistically quantify vertebral pneumaticity in members of the neognath family Ciconiidae (storks), with pneumaticity measured as the relative volume of internal air space. These data are used to describe serial variation in extent of pneumaticity and to assess whether and how pneumaticity varies with the size and shape of a vertebra. Pneumaticity increases dramatically from the middle of the neck onwards, contrary to previous predictions that cervical pneumaticity should decrease toward the thorax to maintain structural integrity as the mass and bending moments of the neck increase. Although the largest vertebrae sampled are also the most pneumatic, vertebral size cannot on its own account for serial or interspecific variation in extent of pneumaticity. Vertebral shape, as quantified by three-dimensional geometric morphometrics, is found to be significantly correlated with extent of pneumaticity, with elongate vertebrae being less pneumatic than craniocaudally short and dorsoventrally tall vertebrae. Considered together, the results of this study are consistent with the hypothesis that shape- and position-specific biomechanics influence the amount of bone loss that can be safely tolerated. These results have potentially important implications for the evolution of vertebral morphology in birds and their extinct relatives.

Risk factors of low back pain and the relationship with sagittal vertebral alignment in Tanzania.

BACKGROUND: LBP is a common and serious problem affecting vast populations of the world. However, only few studies on LBP in sub-Saharan Africa have been conducted. Studies report that LBP and pelvic angle are interrelated, and African residents have a high pelvic tilt. The strategy to prevent LBP should focus on activities that promote holistic health. For that purpose, it is important to grasp the state of LBP and how it affects people's lifestyle in Tanzania to clarify the direction of implementation of physiotherapy treatment and reduce the incidences of LBP among adults. This study aimed to investigate the prevalence and presentation of low back pain (LBP) and the relationship between anthropometric measurements and LBP among people in Moshi city, Kilimanjaro region Tanzania. METHODS: Following signing consent forms, participants were given questionnaires regarding LBP and then grouped accordingly into either asymptomatic or symptomatic cohorts. Anthropometric measurements of participants' height, weight, curvature of the spine, and pelvic angle were obtained. RESULTS: A Mann-Whitney U test analysis showed a significant difference in pelvic angle, body mass index (BMI), and thoracic kyphosis angle between the asymptomatic group and the symptomatic group. No significant differences in lumbar lordosis angle or abdominal muscle strength were found between the two groups. CONCLUSIONS: A person with symptomatic LBP in Tanzania has a large anteversion of the pelvic tilt and a thoracic kyphotic posture. This study shows a relationship between sagittal spinal alignment and LBP in Tanzania, which could allow for prospective identification of subjects prone to developing LBP in the future.

Validity of the Rule of Threes and Anatomical Relationships in the Thoracic Spine.

CONTEXT: The location of the more superficial thoracic spinous processes is used to help osteopathic physicians locate the deeper and more difficult-to-palpate thoracic transverse processes. In 1979, Mitchell et al proposed the thoracic rule of threes to describe the relationship of the spinous processes to the transverse processes in the thoracic spine. This rule is currently taught at osteopathic medical schools. The rule of threes separates the thoracic vertebrae into 3 distinct groups, each with a different relationship between transverse processes and spinous processes. In 2006, Geelhoed et al proposed a new relationship between the spinous processes and transverse processes for all thoracic vertebrae (ie, Geelhoed's rule). OBJECTIVE: To determine which anatomical relationship-the rule of threes or Geelhoed's rule-is most accurate in locating the transverse processes and to define anatomical relationships between thoracic spinous and transverse processes. METHODS: The thoracic spinous and transverse processes of 44 formalin-embalmed human cadavers were dissected, marked, and photographed. Six different measurements per vertebra were made between spinous processes and transverse processes in the thoracic spine. Geelhoed's protocol was used to determine the validity of each rule. The measurements were analyzed for additional relationships between thoracic spinous processes and transverse processes. Group 1 consisted of vertebrae T1 to T3 and T12; group 2 consisted of T4 to T6 and T11; and group 3 consisted of T7 to T10. RESULTS: Of the 528 vertebrae measured, 0% of the first group vertebrae, 10.8% of the second group vertebrae, and 69.3% of the third group vertebrae followed the rule of threes. In total, 26.7% of vertebrae followed the rule of threes, whereas 62.3% of vertebrae followed Geelhoed's rule. Additional relationships worth noting include the distance between the transverse process and the adjacent caudal transverse process on the same side is approximately 25.4 mm (1 inch), and the distance between the transverse processes of the same vertebra is approximately 50.8 mm (2 inches) for male T3-T10 vertebrae and female T1-T12 vertebrae. CONCLUSION: According to our findings, the rule of threes is not as accurate anatomically as Geelhoed's rule in locating the transverse processes of the thoracic spine. This study suggests osteopathic medical schools should teach Geelhoed's rule rather than the rule of threes.

Cortical Thinning and Structural Bone Changes in Non-Human Primates after Single-Fraction Whole-Chest Irradiation.

Stereotactic body radiation therapy (SBRT) is associated with an increased risk of vertebral compression fracture. While bone is typically considered radiation resistant, fractures frequently occur within the first year of SBRT. The goal of this work was to determine if rapid deterioration of bone occurs in vertebrae after irradiation. Sixteen male rhesus macaque non-human primates (NHPs) were analyzed after whole-chest irradiation to a midplane dose of 10 Gy. Ages at the time of exposure varied from 45-134 months. Computed tomography (CT) scans were taken 2 months prior to irradiation and 2, 4, 6 and 8 months postirradiation for all animals. Bone mineral density (BMD) and cortical thickness were calculated longitudinally for thoracic (T) 9, lumbar (L) 2 and L4 vertebral bodies; gross morphology and histopathology were assessed per vertebra. Greater mortality (related to pulmonary toxicity) was noted in NHPs <50 months at time of exposure versus NHPs >50 months ( P = 0.03). Animals older than 50 months at time of exposure lost cortical thickness in T9 by 2 months postirradiation ( P = 0.0009), which persisted to 8 months. In contrast, no loss of cortical thickness was observed in vertebrae out-of-field (L2 and L4). Loss of BMD was observed by 4 months postirradiation for T9, and 6 months postirradiation for L2 and L4 ( P < 0.01). For NHPs younger than 50 months at time of exposure, both cortical thickness and BMD decreased in T9, L2 and L4 by 2 months postirradiation ( P < 0.05). Regions that exhibited the greatest degree of cortical thinning as determined from CT scans also exhibited increased porosity histologically. Rapid loss of cortical thickness was observed after high-dose chest irradiation in NHPs. Younger age at time of exposure was associated with increased pneumonitis-related mortality, as well as greater loss of both BMD and cortical thickness at both in- and out-of-field vertebrae. Older NHPs exhibited rapid loss of BMD and cortical thickness from in-field vertebrae, but only loss of BMD in out-of-field vertebrae. Bone is sensitive to high-dose radiation, and rapid loss of bone structure and density increases the risk of fractures.

[Research progress of Shenshu (BL 23)].

In order to accurately understand the location of Shenshu (BL 23) and to improve the efficacy of acupuncture, a discussion is performed in this paper from aspects of acupoint function, anatomical structure, experiment research, clinical application, etc., hoping to provide benefit for future animal experiments and clinical selection of acupoint. The characteristics of rat spine is different from that of human, and the reliability and authenticity of acupoint location would be compromised if the anatomical characteristics of human was inflexibly applied on animals. "Shenshu" (BL 23) belongs to the bladder meridian of foot taiyang, and is located 1.5 cun lateral to the lower border of the spinous process of the second lumbar vertebra. It is close to kidney, therefore deep insertion or repeated lifting and thrusting of needle would damage kidney and causes acupuncture accident. Therefore, to locate "Shenshu" (BL 23) in rat, the 6th lumbar vertebra is located firstly based on tuber coxae of rat, and then 11th thoracic vertebra is located by upward 4 vertebral bodies or locate 9th to 11th thoracic vertebra which are tight, and finally 2nd lumbar vertebra is located by downward 4 vertebral bodies, and "Shenshu" (BL 23) is 5 mm lateral to it. During clinical treatment, the technique should be gentle; oblique and outward insertion of needle is not allowed; the maximum depth of needle insertion is 1.6 cun (approximately 4.30 cm); the vertical or oblique insertion with needle 45° towards spine is appropriate; the depth of 0.8 to 1.2 cun (2.00 to 3.10 cm) is suitable. In cases of too thin or fat patients, the depth of needle insertion should be adjusted for safety.

[Methods for Accurately Locating "Feishu" (BL 13) in Rats].

"Feishu" (BL 13) is a commonly used acupoint in experimental study,'but its definite position has not been described in current books about acupoints. In the'present paper, the authors introduced three methods for determining the anatomical location of "Feishu" (BL 13) acupoint in rats. The Wistar rats (200 ± 20) g were anesthetized with 10% chloral hydrate first, and then, fixed at the prone position. The highest point of the spinous process of the second thoracic vertebra was used as the marker for positioning the spinal vertebra. The point, 7 mm lateral to the site below the spinous process of the 3rd thoracic vertebra is just the "Feishu" (BL 13). In order to determine the 3rd thoracic vertebra, three methods are recommended to be adopted: 1) finding the 5th thoracic vertebra process parallel to the inferior angle of the scapula first, then going upwards to find the 3rd thoracic vertebra , 2) finding the 1st thoracic vertebra along the 1st rib, then going downward to find the 3rd thoracic vertebra, and 3) taking the 6th lumbar vertebra (parallel to the hip-joint) as the bone-marker and going upward to find the 3rd thoracic vertebra. When "Feishu" (BL 13) punctured, a filiform needle was straight inserted into the skin, then downward to the subcutaneous tissue, muscular layer (including the trunk cutaneous muscle, trapezius muscle, broadest muscle of back, serratus muscle of back, atalanto-longest muscle, longest muscle of neck, longest muscle of thorax, lumbar longest muscle, the medial part of the longest muscle, cervico-spinal muscle of back-, semispinal muscle of neck, biventer cervicis, and multifidus muscles) about 6 mm in depth.

Inter-individual variability of bone density and morphology distribution in the proximal femur and T12 vertebra.

Bone geometry, density and microstructure can vary widely between subjects. Knowledge about this variation in a population is of interest in particular for the design of orthopedic implants and interventions. The goal of this study is to investigate the local variability of bone density and microstructural parameters between subjects using a novel inter-subject image registration approach. Human proximal femora of 29 and T12 vertebrae of 20 individuals were scanned using a HR-pQCT and a micro-CT system, respectively. A pre-defined iso-anatomic mesh template was morphed to each micro-CT scan. For each element bone volume fraction and other morphological parameters (Tb.Th, Tb.N, Tb.Sp, SMI, DA) were determined and assigned to the element. A coefficient of variation (CV) was calculated for each parameter at each element location of the 29 femora and 20 T12 vertebrae. Contour plots of the CV distribution revealed very detailed information about the inter-individual variation in bone density and morphology. It is also shown that analyzing large sub-volumes, as commonly done in previous studies, would miss much of this variation. Detailed quantitative information of bone morphological parameters for each sample in the femur and the T12 database and their inter-individual variability are available from the mesh templates as supplementary data (http://w3.bmt.tue.nl/nl/fe_database/). We expect that these results can help to optimize implants and orthopedic procedures by taking local bone morphological parameter variations into account.

Accidental subdural spinal cord stimulator lead placement and stimulation.

OBJECTIVES: Neuromodulation with spinal cord stimulation has become an increasingly employed intervention for treatment of a variety of neuropathic pain states. As prevalence increases, so does the incidence of complications. Currently, there is sparse literature describing spinal cord stimulation lead placement and stimulation characteristics in the subdural space. In this case report we describe subdural lead placement and the associated stimulation parameters, and provide evidence-based support to initiate a dialog to further reduce procedural morbidity and mortality. MATERIALS AND METHODS: This study is a case report following lead placement during permanent percutaneous spinal cord stimulator placement and stimulation testing. The lead placement and stimulation characteristics were suggestive of extra-epidural lead placement. RESULTS: Using the same cathode/anode configuration (1:anode, 3:cathode, 5:anode), frequency of 40 Hz and pulse width of 650 microseconds, sequential stimulation was performed. Summarizing, the testing demonstrated similar impedance for the left and right leads (within 30 ohms) of approximately 300 ohms, and a large discrepancy in current of 3.2 mA for the left and 0.9 mA for the right. The patient reported "painful intense" stimulation with right lead stimulation. CONCLUSIONS: Evidence suggesting subdural lead placement include the lack of cerebrospinal-fluid despite lavage, the absence of post-dural puncture headache, the recent evidence of intentional and reproducible subdural anesthesia, and the conductive properties of the dural spinal elements. It can be argued that subdural lead placement may occur unrecognized more frequently than originally anticipated.

Increased microstructural variability is associated with decreased structural strength but with increased measures of structural ductility in human vertebrae.

The lack of accuracy in the prediction of vertebral fracture risk from average density measurements, all external factors being equal, may not just be because bone mineral density (BMD) is less than a perfect surrogate for bone strength but also because strength alone may not be sufficient to fully characterize the structural failure of a vertebra. Apart from bone quantity, the regional variation of cancellous architecture would have a role in governing the mechanical properties of vertebrae. In this study, we estimated various microstructural parameters of the vertebral cancellous centrum based on stereological analysis. An earlier study indicated that within-vertebra variability, measured as the coefficient of variation (COV) of bone volume fraction (BV/TV) or as COV of finite element-estimated apparent modulus (E(FE)) correlated well with vertebral strength. Therefore, as an extension to our earlier study, we investigated (i) whether the relationships of vertebral strength found with COV of BV/TV and COV of E(FE) could be extended to the COV of other microstructural parameters and microcomputed tomography-estimated BMD and (ii) whether COV of microstructural parameters were associated with structural ductility measures. COV-based measures were more strongly associated with vertebral strength and ductility measures than average microstructural measures. Moreover, our results support a hypothesis that decreased microstructural variability, while associated with increased strength, may result in decreased structural toughness and ductility. The current findings suggest that variability-based measures could provide an improvement, as a supplement to clinical BMD, in screening for fracture risk through an improved prediction of bone strength and ductility. Further understanding of the biological mechanisms underlying microstructural variability may help develop new treatment strategies for improved structural ductility.

Percutaneous approach to the upper thoracic spine: optimal patient positioning.

Percutaneous access to the upper thoracic vertebrae under fluoroscopic guidance is challenging. We describe our positioning technique facilitating optimal visualisation of the high thoracic vertebrae in the prone position. This allows safe practice of kyphoplasty, vertebroplasty and biopsy throughout the upper thoracic spine.

Sectional neuroanatomy of the lower thoracic spine and chest.

This is the fourth in a series of articles on the spine. The first reviewed the anatomy of the neck; the second reviewed the upper thoracic spine and chest (T1-T4); and the third reviewed the middle thoracic spine and chest (T5-T8). The procedures performed in the lower thoracic spine include percutaneous biopsies of the liver and kidneys, percutaneous nephrolithotomy, spinal injections, radiofrequency ablations, electromyography of the diaphragm, trigger point injections, chemodenervation with botulinum toxin, acupuncture, aneurysm repair, and, occasionally, chest tube placement in the lower lung fields. Complications include subcapsular hematomas, infections, pneumothorax, hemothorax, spinal cord ischemia and resultant paraplegia, and, rarely, nephropleural fistulas. This article provides anatomically accurate schematics of innervations of the lower thoracic chest and spine (T9-T12) that can be used to interpret the magnetic resonance images of the muscles and the nerves. Cross-sectional schematics of the lower thoracic chest and spine were drawn as they appear on imaging projections. The relevant nerves were color coded. The muscles and skin surfaces were labeled and assigned the color of the appropriate nerves. An organized comprehensive map of the motor innervation of the lower thoracic chest and spine allows the physician to increase the accuracy and the efficacy of interventional procedures. This could also assist the electromyographer in correlating the clinical and electrophysiological findings with magnetic resonance images.

[Anatomical basis and technique of thoracic paravertebral blockade]. / Podstawy anatomiczne i technika wykonania piersiowej blokady przykregowej.

This article presents in illustrations the classical technique of transdermal identification and anatomy of paravertebral space (PVS) comparing to other techniques. This have to be acknowledged by anaesthesiologists as well as by other specialists to perform thoracic paravertebral blockade (TPVB)--earlier elapsed but nowadays getting more popular--safely. In addition the article contains a short description of author's own modification of Eason's and Wyatt's technique.

The effects of transforaminal ligaments on the sizes of T11 to L5 human intervertebral foramina.

OBJECTIVE: This study was designed to determine the effects of the presence of transforaminal ligaments (TFL) on the superior-to-inferior dimension (SI) and anterior-to-posterior dimension (AP) of the compartment containing the ventral ramus of the spinal nerve (VR) in the intervertebral foramen (IVF). DESIGN: Four lumbar spines, including T12 and in one case T11, were obtained from embalmed cadavers and carefully dissected to expose the contents of the IVF. All ligamentous structures in the vicinity of the IVF were preserved. The greatest SI and AP of each IVF were measured. When present, TFL help define a compartment at the exit zone of the IVF that contains the VR. The SI and AP of these compartments were also measured. RESULTS: Of 49 IVF examined, at least one TFL was present in 35. In the 34 IVF with horizontally oriented TFL, the mean SI of the compartments for the VR was 31.5% smaller than that of the IVF (one-way ANOVA, p < .01). No significant differences were seen between the AP of the IVF and compartments for the VR in the levels with vertically oriented TFL (n = 11). CONCLUSIONS: TFL were found to be present in 71% of lower thoracic and lumbar IVF. If TFL were present, the SI of the compartment containing the VR in the IVF was significantly decreased (mean = 31.5%). This finding suggests that often there may be less space at the exit zone of the IVF for the ventral ramus than traditionally thought, which could contribute to the incidence of neurological symptomatology in this region, especially after trauma or degenerative changes.

Influence of zygapophyseal joint orientation on hyaline cartilage at the thoracolumbar junction.

Hyaline articular cartilage from 102 thoracolumbar junction zygapophyseal joints was examined using light microscopy. One section from the upper, middle and lower third of each joint at the T10-11, T11-12, T12-L1 and L1-2 spinal levels was photographed using 35 mm color film. Hyaline articular cartilage cross-sectional area of the superior and inferior articular processes of each joint pair, at each level, was digitized using computer-aided planimetry. Differences in area were compared with joint orientation (symmetry or tropism) and geometry of each joint pair at each spinal level. Variation in hyaline cartilage cross-sectional area between joint pairs could be attributed to: a) geometric differences, b) the presence of a mortice joint, or c) osteoarthritic changes, with or without tropism. These findings were most frequently demonstrated at the transitional levels of T11-12 and T12-L1.

Manual therapy considerations at the thoracolumbar junction: an anatomical and functional perspective.

Anatomically, the human thoracolumbar junction demonstrates considerable resistance to rotary motion in an effort to decrease torsional stress through an area of marked functional transition. Despite this, rotational manipulation and mobilization procedures have been advocated in the treatment of painful mechanical disorders originating from the thoracolumbar junction. The rationale behind vigorous manipulative techniques, particularly those incorporating extension, is challenged in light of cadaveric histological studies of this region, as well as both in vivo and experimental biomechanical investigations. Judicious use of traction and mobilization procedures are recommended.