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C F Hoffmann

Publications and source records attributed to C F Hoffmann.

8 recordsLinked to original sources
PubMed1999

Initial report on the limited value of hypoglossal nerve transfer to treat brachial plexus root avulsions.

OBJECT: Hypoglossal nerve (12th cranial nerve) transfer was performed to treat the sequelae of brachial plexus root avulsion in 12 adults and two infants, and the patients were followed to assess the effectiveness of the surgery. METHODS: The 12th cranial nerve was transected at the base of the tongue, and a sural nerve graft was used to bridge the gap between the donor (12th) and recipient nerves: C-5 spinal, axillary, suprascapular, or musculocutaneous nerve. The mean graft length in adult patients was 15.75 +/- 5.5 cm (+/- standard deviation, median 14.5 cm) and in the two infants the graft lengths were 7 and 8 cm, respectively. After a mean postoperative interval of 1138 +/- 254 days, electromyographic examination of the target muscles showed tongue movement-related activity in all patients. Muscle force strength measured according to the Medical Research Council's guidelines, was Grade 3 or higher in 21% of patients. Contraction, however, could only be attained by tongue movements, and volitional control was not achieved. CONCLUSIONS: Although recovery of muscle strength was obtained by 12th cranial nerve transfer, the functional gain remained virtually nonexistent because central control was missing.

Adolescent↗
PubMed1996

Reinnervation of avulsed and reimplanted ventral rootlets in the cervical spinal cord of the cat.

Spinal nerve root avulsions frequently occur in brachial plexus injuries caused by traction. Such lesions are considered to afflict the central nervous system (CNS) and are, therefore, believed to be beyond surgical repair. The present experimental study was initiated to challenge this hypothesis. The ventral rootlets of C-7 were avulsed from the spinal cord in 28 cats via an anterior approach and subsequently reimplanted into the cord at the site of origin. In nonoperated control cats and cats undergoing reimplantation, electrophysiological experiments were performed and horseradish peroxidase was administered to the spinal nerve on the reimplanted side after survival times ranging from 6 to 293 days. Spinal cord sections in all cats were stained for neurofilament, acetylcholinesterase (AChE), Nissl, and glial fibrillary acidic protein. Horseradish peroxidase-labeled ventral horn motoneurons were found as early as 14 days after reimplantation and their number increased with time. On Days 209 and 293, the number of labeled neurons equaled the number of labeled ventral horn neurons in the two control cats that did not undergo surgery. Starting on Day 6 after reimplantation, the appearance of the ventral horn and the white matter in the neurofilament, AChE, and Nissl-stained sections changed as a result of the CNS response to the injury. A return to their normal appearance could be observed in these stainings from Day 209 onward. Glial fibrillary acidic protein-positive astrocytic tissue was consistently found in the ventral horn and in the white matter reimplantation area. From Day 69 onward, electrophysiological stimulation of the spinal nerve C-7 on the reimplanted side elicited an electromyogram response in the spinodeltoid muscle. The latency and threshold intensity of the C-7 responses were initially increased but equalized to match the nonoperated controls between 98 and 122 days after reimplantation. The results of this study show that functional regeneration of ventral horn neurons after root avulsion and subsequent reimplantation in the cat is possible.

Acetylcholinesterase↗
PubMed1993

Neuroradiological investigations in cervical root avulsion.

Cervical myelography in combination with CT myelography is not fully reliable to demonstrate a partial or complete cervical root avulsion. MRI scanning can demonstrate large traumatic meningoceles or additional lesions, such as intramedullary or extradural haematomas, but not a root avulsion. In experimental conditions MR microscopy enables visualization of the avulsed root separated from the spinal cord. The anterior funiculus shows transverse tracts left behind by the avulsion at the original site of the motor fibres. However, the small bore of the current high field magnets and the very long acquisition time makes this method, as yet, unsuitable for application in man.

Brachial Plexus↗
PubMed1993

Ultrastructural study on avulsion effects of the cat cervical moto-axonal pathways in the spinal cord.

After selective avulsion of the ventral root cervical 7 (C7) from the adult cat spinal cord, the intraspinal trajectories of the torn axons in the white matter were studied at different survival times. Two phases could be discerned: an early phase which showed changes that occurred up to 14 days after avulsion and a second phase from day 30 onwards. Two days postoperatively, considerably swollen, empty myelin sheaths occurred, which remained present up to 14 days after avulsion. A primary increase in the number of glial cells (microglia) was noted on days 2 and 4 after avulsion. Ultrastructurally, unmyelinated and myelinated terminal clubs were found 8 and 14 days after avulsion. These clubs were characterized as cones of growth, related to axonal regeneration. A second glial increase was present after 30 days. At that time, the entire moto-axonal pathway clearly showed a degeneration pattern. This finding was light microscopically confirmed by an increase of GFAP-positive astrocytes. During the first 30 days, a front of small calibre myelinated axons, starting at the transition zone of the grey and white matter traversed halfway through the moto-axonal pathway. However, on days 60 and 90 no further shift of the front had occurred.

Animals↗
PubMed1993

Reimplantation of ventral rootlets into the cervical spinal cord after their avulsion: an anterior surgical approach.

Root avulsions from the cervical spinal cord due to traction injuries are beyond repair up to the present day. An anterior surgical approach has been developed in cats for reimplantation of the ventral rootlets into the site of avulsion. The consecutive surgical steps towards exposure of the ventral surface of the cervical cord are given in detail. The morphological relations during the operative procedure are explained in the text and by illustrations. In this study the surgery related mortality rate was 16% and the overall mortality rate amounted to 21%. Loss of blood, initially a major problem, was coped with by increasing technical experience and the infusion of plasma expanding fluid. In 2 animals with survival times of 209 and 293 days respectively, many ventral horn motoneurons were found HRP-positive after retrograde HRP transport through the site of reimplantation. The findings provide evidence that the axonal continuity between reimplanted ventral roots and their motoneurons may be restored.

Animals↗
PubMed1990

Ventral root avulsions of the cat spinal cord at the brachial plexus level (cervical 7).

The ventral cervical 7th root was avulsed from the surface of the cat spinal cord, and studied using light microscopical stainings (Nissl, acetylcholinesterase and antibodies against neurofilament and glial fibrillary acidic protein) after different survival times. After two days the density of the neurofilament increased in the neurons in the ventral horn of the avulsed ventral root. Changes in the rough endoplasmatic reticulum (Nissl and acetylcholinesterase) started four days postoperatively, and were confirmed electron microscopically. The glial fibrillary acidic protein-positive structures surrounding the injured neurons in the avulsed ventral horn became more pronounced 30 days postoperatively. The number of neurons was definitely decreased 60 days after the avulsion. After the initial phase of the avulsion and before the distinct decrease in the number of neurons, the conditions for reimplantation of the avulsed ventral root and for the supposed regeneration can be expected to be more favourable for the neurons in the ventral horn.

Acetylcholinesterase↗