Ventral root avulsion versus transection at the cervical 7 level of the cat spinal cord

This review summarises studies aiming at a surgical treatment of spinal nerve root avulsions from the spinal cord in brachial plexus lesions. After dorsal root injury, regrowth of nerve fibres into the spinal cord occurs only in the immature animal. After ventral root avulsion and subsequent implantation into the spinal cord, neuroanatomical and neurophysiological data show that motoneurons are capable of producing new axons which enter the implanted root. Intra-neuronal physiological experiments demonstrate that new axons can conduct action potentials and elicit muscle responses. The neurons are reconnected in segmental spinal cord activity and respond to impulses in sensory nerve fibres. In primate experiments, implantation of avulsed ventral roots in the brachial plexus resulted in functional restitution. These studies indicate the possibility of surgical treatment of ventral root avulsion injuries in brachial plexus lesions in humans.

Download Full-text

Modulation of the visceromotor reflex by a lumbosacral ventral root avulsion injury and repair in rats

AJP Renal Physiology ◽

10.1152/ajprenal.00094.2012 ◽

2012 ◽

Vol 303 (5) ◽

pp. F641-F647 ◽

Cited By ~ 8

Author(s):

Huiyi H. Chang ◽

Leif A. Havton

Keyword(s):

Cauda Equina ◽

Experimental Models ◽

Ventral Root ◽

Oblique Muscle ◽

Emg Activity ◽

Noxious Stimulation ◽

Electromyographic Activity ◽

Root Avulsion ◽

Contraction Duration ◽

Ventral Root Avulsion

Increased abdominal muscle wall activity may be part of a visceromotor reflex (VMR) response to noxious stimulation of the bladder. However, information is sparse regarding the effects of cauda equina injuries on the VMR in experimental models. We studied the effects of a unilateral L6-S1 ventral root avulsion (VRA) injury and acute ventral root reimplantation (VRI) into the spinal cord on micturition reflexes and electromyographic activity of the abdominal wall in rats. Cystometrogram (CMG) and electromyography (EMG) of the abdominal external oblique muscle (EOM) were performed. All rats demonstrated EMG activity of the EOM associated with reflex bladder contractions. At 1 wk after VRA and VRI, the duration of the EOM EMG activity associated with reflex voiding was significantly prolonged compared with age-matched sham rats. However, at 3 wk postoperatively, the duration of the EOM responses remained increased in the VRA series but had normalized in the VRI group. The EOM EMG duration was normalized for both VRA and VRI groups at 8–12 wk postoperatively. CMG recordings show increased contraction duration at 1 and 3 wk postoperatively for the VRA series, whereas the contraction duration was only increased at 1 wk postoperatively for the VRI series. Our studies suggest that a unilateral lumbosacral VRA injury results in a prolonged VMR to bladder filling using a physiological saline solution. An acute root replantation decreased the VMR induced by VRA injury and provides earlier sensory recovery.

Download Full-text