Changes in the Termination of Spinal Cord at Vertebral Levels during Pre- and Postnatal Development of Sheep

Ghazi, S R; Gholami, Somayeh

doi:10.1080/09712119.1993.9705975

Cited by 6 publications

(5 citation statements)

References 7 publications

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“…The size and configuration of the sheep spinal cord and spinal canal are well suited for studies of I-Patch mechanics and investigations of electrical interface properties between electrode contacts and the spinal cord. Additionally, the anatomy and physiological properties of the sheep peripheral and central somatosensory systems are well described (Dolan and Nolan 2002, Flo et al 2009, Ghazi and Gholami 1993a, 1993b, Herrero and Headley 1995a, 1995b, 1995c, Johnson et al 1974, Rose 1942, Vialle et al 2006, Wilson and Beerwinkle 1986. The institutionally approved, acute, non-survival experiments described in this report were all carried out under general anesthesia: inhaled isofluorane was used for induction and during the surgical dissections, followed by continuous infusion of propofol (0.4 mg kg −1 h −1 ) during experimentation and data acquisition.…”

Section: Experimental Preparationmentioning

confidence: 99%

A new device concept for directly modulating spinal cord pathways: initialin vivoexperimental results

Flouty¹,

Oya²,

Kawasaki³

et al. 2012

Physiol. Meas.

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We describe a novel spinal cord (SC) stimulator that is designed to overcome a major shortcoming of existing stimulator devices: their restricted capacity to selectively activate targeted axons within the dorsal columns. This device overcomes that limitation by delivering electrical stimuli directly to the pial surface of the SC. Our goal in testing this device was to measure its ability to physiologically activate the SC and examine its capacity to modulate somatosensory evoked potentials (SSEPs) triggered by peripheral stimulation. In this acute study on adult sheep (n = 7), local field potentials were recorded from a grid placed in the subdural space of the right hemisphere during electrical stimulation of the left tibial nerve and the spinal cord. Large amplitude SSEPs (>200 µV) in response to SC stimulation were consistently obtained at stimulation strengths well below the thresholds inducing neural injury. Moreover, stimulation of the dorsal columns with signals employed routinely by devices in standard clinical use, e.g., 50 Hz, 0.2 ms pulse width, produced long-lasting changes (>4.5 h) in the SSEP patterns produced by subsequent tibial nerve stimulation. The results of these acute experiments demonstrate that this device can be safely secured to the SC surface and effectively activate somatosensory pathways.

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Section: Experimental Preparationmentioning

confidence: 99%

A new device concept for directly modulating spinal cord pathways: initialin vivoexperimental results

Flouty¹,

Oya²,

Kawasaki³

et al. 2012

Physiol. Meas.

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“…These ndings indicated a signi cant change in the termination point of the spinal cord even after birth. Furthermore, the regression process can continue throughout an animal's adult life [25]. In dogs, a signi cant difference between the position of the DS and the dog's weight has been found [22].…”

Section: Discussionmentioning

confidence: 99%

Computed Tomography Assessment of the Conus Medullaris and the Dural Sac Termination in Adult Sheep: Anatomical Implications for Lumbosacral and Sacrococcygeal Injections

Gutiérrez-Bautista,

García-Roselló,

Redondo

et al. 2024

Preprint

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This study aimed to provide information about the conus medullaris (CM) and dural sac (DS) termination points in sheep. Thirteen adult Merino-mixed sheep were anaesthetised and underwent lumbosacral computed tomography (CT) myelography. A spinal injection was administered using a Tuohy needle while the sheep were in sternal recumbency. After confirming the presence of cerebrospinal fluid, 0.4 ml kg-1 iodinated contrast media was injected, and a CT scan was conducted. The analysis focused on determining the vertebrae at which the CM and DS ended. The results showed that in eight cases, the conus ended at the first sacral vertebra, while in five sheep, the termination point was identified at the level of the second sacral vertebra. DS termination occurred in the 3rd sacral vertebra in one animal, the 4th sacral vertebra in another sheep, the 1st caudal vertebra in six cases, and the 2nd caudal vertebra in five cases. The findings highlight the need for caution during lumbosacral injections in sheep, as the CM concludes caudally to this space. It is also essential to be aware that the DS persists caudal to the sacrococcygeal space for safe epidural injections in this region.

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“…Ascension occurs mainly during the prenatal (Arthurs et al, 2013; Barson, 1970; Vettivel, 1991) and the early postnatal (Barson, 1970; Vettivel, 1991) period. It is most pronounced in the lower subdivisions of the spinal cord, the lumbar and sacral regions (Ghazi & Gholami, 1993a; Gholami et al, 1997; Sakla, 1969). It is assumed that the adult level of ascension is reached due to the faster growth of the vertebral column in relation to the spinal cord (Sakla, 1969) and probably because of the formation of cervical and lumbar enlargements (Lebedkin, 1937).…”

Section: Introductionmentioning

confidence: 99%

“…It is assumed that the adult level of ascension is reached due to the faster growth of the vertebral column in relation to the spinal cord (Sakla, 1969) and probably because of the formation of cervical and lumbar enlargements (Lebedkin, 1937). The most of developmental studies of ascension are based on the position of the conus medullaris (i.e., the beginning of the filum terminale ; human: Barson, 1970; Wolf et al, 1992; Van Schoor et al, 2015; sheep: Ghazi & Gholami, 1993a; aquatic and semiaquatic animals: Sobolevskiĭ, 1978; camel: Gholami et al, 1997; cat: Ghazi et al, 2004). However, the ascension can also be accompanied by the descension of some spinal regions due to their unequal growth rate (sloth: Goffart et al, 1967; rat: Istaith, 1975; impala: Rao et al, 1993; cat: Maierl & Liebich, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…However, the ascension can also be accompanied by the descension of some spinal regions due to their unequal growth rate (sloth: Goffart et al, 1967;rat: Istaith, 1975;impala: Rao et al, 1993;cat: Maierl & Liebich, 1998). A few studies examine the change of the absolute lengths of the spinal cord regions (cervical, thoracic, lumbar, or sacral; rhesus: Hines & Emerson, 1951;albino mouse: Sakla, 1969;rat: Istaith, 1975;cat: Mellström & Skoglund, 1969;Maierl & Liebich, 1998) or the changes in their relative lengths (goat: Maya et al, 2008;Ghazi et al, 2016); the contribution of individual segments to the development of ascension and to the establishment of the positions of the segments typical for an adult individual, has been poorly investigated. Only one study checked the relative segment length of sheep fetuses' spinal cord compared to a group of adult animals (Ghazi & Gholami, 1994).…”

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confidence: 99%

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Postnatal growth of the lumbosacral spinal segments in cat: Their lengths and positions in relation to vertebrae

Shkorbatova

Lyakhovetskii

Veshchitskii

et al. 2022

The Anatomical Record

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Cat is a prominent model for investigating neural networks of the lumbosacral spinal cord that control locomotor and visceral activity. We previously proposed an integral function, establishing the topographical relationship between the spinal cord segments and vertebrae in adult animals. Here, we investigated the dynamic of this topographical relationship through early and middle periods of development in kittens. We calculated the length of each vertebra relative to the total length of the region from 13th thoracic (T) to the 7th lumbar (L) vertebrae (V) as well as the length of each segment relative to the total region from T13 to the three-dimensional sacral (S) segment. As in our previous work, the length and position of VL2 were used to establish relationships between the characteristics of the segments and vertebrae. Cubic regression reliably approximates the lengths of segments relative to VL2 length. As the cat aged, the relative length of VT13 and VL1 decreased while the relative length of VL5 increased. The relative length of the T13 and L3 segments increased while the relative length of the S1-S2 segments decreased. The T13-L2 segments are descended monotonically relative to the VL1-VL2 border.The L3-S1 segments are also descended, though with more complex dynamics.The positions of the S2-S3 segments remained unchanged. To conclude, different spinal segments displayed different developmental dynamics. The revealed relationship between vertebrae and lumbosacral spinal segments may be helpful for clearly defining stimulation regions to invoke particular functions, both in experimental studies on the spinal cord and clinical treatment.

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Changes in the Termination of Spinal Cord at Vertebral Levels during Pre- and Postnatal Development of Sheep

Abstract: Ghazi, S. R and Gholami, S. 1993

Cited by 6 publications

References 7 publications

A new device concept for directly modulating spinal cord pathways: initialin vivoexperimental results

A new device concept for directly modulating spinal cord pathways: initialin vivoexperimental results

Computed Tomography Assessment of the Conus Medullaris and the Dural Sac Termination in Adult Sheep: Anatomical Implications for Lumbosacral and Sacrococcygeal Injections

Postnatal growth of the lumbosacral spinal segments in cat: Their lengths and positions in relation to vertebrae

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