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Biomedical subjects

R L Tiel

Publications and source records attributed to R L Tiel.

10 recordsLinked to original sources
PubMed2002

Accumulation of PN1 and PN3 sodium channels in painful human neuroma-evidence from immunocytochemistry.

BACKGROUND: The axolemmal distribution and density of voltage-gated sodium channels largely determines the electrical excitability of sprouting neurites. Recent evidence suggests that accumulation of sodium channels at injured axonal tips may be responsible for ectopic axonal hyperexcitability and the resulting abnormal sensory phenomena of pain and paresthesias. For future improvement in pain management it is necessary to identify structurally significant generators of autorhythmicity. A first step in this regard will be to determine the predominant types of sodium channels in injured axons. The opportunity to test human specimens from painful and non-painful neuroma is of great value. METHODS: We employed immunocytochemical methods to investigate if two types of highly specific voltage-gated sodium channel subtypes could be detected in sections of human neuroma. FINDINGS: Both subtypes of sodium channels PN1 and PN3 accumulated abnormally in human neuromas. The immunoreactive pattern was more pronounced in painful neuromas. This is in contrast to previous reports that focused either on PN1 or PN3 as main generators of hyperexcitability induced pain. INTERPRETATION: Both, PN1 and PN3 seem to be involved in hyperexcitability induced pain. It can be expected that a variety of other highly specific voltage gated sodium channel subtypes will be detected in regenerating peripheral nerve in the near future, which contribute to the development of neuropathic pain states. Thus, in order to therapeutically control hyperexcitability induced neuropathic pain, it might be worthwhile to develop pharmaceuticals that can selectively block different sodium channel subtypes and subunits.A review of the role of sodium channels in neuropathic pain is implemented in the discussion.

Humans↗
PubMed2001

Outcomes in a consecutive series of 111 surgically treated plexal tumors: a review of the experience at the Louisiana State University Health Sciences Center.

OBJECT: The authors conducted a retrospective study of 107 consecutive patients with 111 brachial plexus tumors surgically treated at the Louisiana State University Health Sciences Center (LSUHSC). METHODS: During a 12-year period, from 1986 to 1998, 371 patients with lesions of the brachial plexus underwent surgery at LSUHSC. Among this group, 107 patients harbored 111 tumors of the brachial plexus. Neural sheath tumors were the most commonly found and included 33 neurofibromas (20 of which were associated with von Recklinghausen disease), 36 schwannomas, and 12 malignant neural sheath tumors. Of the non-neural sheath tumors, 13 were benign and 17 were malignant. Presenting symptoms included pain (59%), palpable mass (52%), paresthesias (30%), and paresis (29%). Anterior supraclavicular (82%) or posterior subscapular (18%) approaches were used to achieve gross-total (79%) or subtotal (21%) resection of tumor. The average follow-up period was 38.3 months or 3.2 years. Seventy percent of patients with benign neural sheath tumors became free from pain postoperatively or reported improvement in their preoperative pain status. Function remained intact or improved in 50% and remained stable postoperatively in another 20% of cases. Preservation of function was more likely in patients who presented intact and in those who had not undergone a previous attempted biopsy procedure or resection than in those in whom such manipulation had occurred. CONCLUSIONS: Resection of most plexal tumors is technically feasible and associated with acceptable morbidity and mortality rates.

Adolescent↗
PubMed2001

Surgical management and outcome in patients with radial nerve lesions.

OBJECT: The goal of this paper was to review surgical management and outcomes in patients treated for radial nerve (RN) lesions at Louisiana State University Health Sciences over a period of 30 years. METHODS: Two hundred sixty patients with RN injuries were evaluated. The most common mechanisms of injuries involving the RN included fracture of the humerus, laceration, blunt contusions, and gunshot wounds. One hundred and eighty patients (69%) underwent surgery. Lesions not in continuity required primary or secondary end-to-end suture repairs or graft repairs. With the use of direct intraoperative nerve action potential recording, RN injuries in which the lesion was in continuity required external or internal neurolysis or resection of the lesion followed by end-to-end suture or graft repair. A minimum of 1.5 years follow-up review was available in 90% of the patients who underwent surgery. Motor function recovery to Grade 3 or better was observed in 10 (91%) of 11 patients who underwent primary suture repair, 25 (83%) of 30 who underwent secondary suture repair, 43 (80%) of 54 who received graft repair, and 63 (98%) of 64 in whom neurolysis was performed. Sixteen (71%) of 21 patients with superficial sensory RN injury achieved satisfactory pain relief after complete resection of a neuroma or neurolysis. CONCLUSIONS: This study clearly demonstrates that excellent functional recovery can be achieved with proper surgical management of RN injuries.

Adolescent↗
PubMed2001

Surgical management and outcomes in patients with median nerve lesions.

OBJECT: One hundred sixty-seven of 250 patients with median nerve (MN) lesions, excluding carpal tunnel syndrome and nerve sheath tumors, at the levels of the arm, elbow, forearm, and wrist, underwent surgical treatment at Louisiana State University Health Sciences over a 30-year period. The most common causes of MN injuries were laceration, fracture-associated stretch and contusion, gunshot wound, compression, and injection injuries. In this study, surgically treated patients were followed and evaluated retrospectively for favorable functional outcomes. METHODS: Lesions not in continuity required primary or secondary end-to-end suture or graft repairs. With the aid of direct intraoperative recording of nerve action potentials (NAPs), MN injuries in which the lesion was in continuity underwent external or internal neurolysis, or resection of the lesion, followed by end-to-end suture or graft repair. A minimum of 12 months follow-up review (mean 18 months) was available in 85% of the surgically treated patients. For lesions in continuity, a functional recovery of Grade 3 or better was seen in 72 (95%) of 76 patients who underwent neurolysis, 18 (86%) of 21 who received suture repair, and 21 (75%) of 28 who received graft repair. In lesions not in continuity, favorable results (Grade > or = 3) were seen in 10 (91%) of 11 patients who received primary suture repair, seven (78%) of nine who received secondary suture repair, and 15 (68%) of 22 who received graft repair. CONCLUSIONS: Surgical intervention for MN injuries with complete or severe deficits achieved favorable outcomes.

Adolescent↗
PubMed1999

AAEM case report 33: costoclavicular mass syndrome. American Association of Electrodiagnostic Medicine.

A true costoclavicular mass syndrome associated with a brachial plexopathy is rare. We report the occurrence of a severe brachial plexopathy as a late complication of a displaced midclavicular fracture. An exuberant callus associated with the clavicular fracture acted as a mass lesion to compress the brachial plexus within the costoclavicular space (i.e., between the clavicle and the first rib). The clinical features and the electrodiagnostic findings in this patient were crucial in suggesting the diagnosis, which was subsequently confirmed by radiographic studies and surgical exploration. Surgical excision of the hyperabundant callus and freeing of the entrapped brachial plexus resulted in marked improvement of the patient's neurological symptoms. Recognition of this uncommon complication of a clavicular fracture is important for the timely diagnosis of this treatable problem.

Aged↗
PubMed1997

Ganglion cyst involvement of peripheral nerves.

Despite their benign histological appearance and the current literature composed primarily of case reports with favorable outcomes, ganglion cysts involving peripheral nerves (GCPNs) can cause permanent neurological deficits. The authors present a 27-year Louisiana State University Medical Center (LSUMC) experience with the surgical management of GCPNs. From 1968 to 1995, 27 patients were surgically treated for 27 cysts that involved nerves at nine locations. Cysts of the peroneal nerve were the most common, comprising 52% of the cases. Motor deficit, pain, and sensory changes were present in 83%, 78%, and 48% of cases, respectively. A history of acute trauma was noted in 22%. The mean follow-up duration in these cases was 61 months. Motor recovery was good in only 58% of cases and was related to the severity of the preoperative motor deficit. Pain resolved or was significantly improved in 89% of cases. Five patients underwent nine procedures before referral to LSUMC for treatment of recurrence of their ganglion cysts. None of these patients suffered recurrence after undergoing surgery at LSUMC. However, four additional patients (17%) experienced a total of six recurrences after undergoing their initial procedure. The mean time to recurrence for the patient group as a whole was 16 months. On the basis of their experience, the authors conclude that GCPNs can behave in an aggressive fashion. Patients should be counseled preoperatively about the potential for limited motor recovery and a significant chance for recurrence.

Adolescent↗
PubMed1996

Nerve action potential recording method and equipment.

OBJECTIVE: Nerve action potential (NAP) recording is a proven and useful tool in the surgical management of nerve injury. Understanding its materials and methods as well as its pitfalls and limitations is necessary for successful and routine use of this tool. METHODS: The basic electrophysiology of nerve and its implications in the setting of nerve trauma and regeneration are reviewed. Electrode design and electrode placement are discussed. The use of simple electromyographic/nerve conduction machines for intraoperative recording of NAPs is developed, along with some of the technical problems that result from electrophysiological recording in an electrically hostile environment. RESULTS: NAP recording is a good indicator of useful recovery in nerve trauma. The presence and demonstration of an NAP is associated with a 90% chance of recovery to a useful motor state. CONCLUSION: NAP recording provides useful information regarding the regenerative potential of a damaged nerve long before that potential is clinically evident. This information is critical in the optimal management of nerve injuries. The techniques of NAP recording are straightforward, but attention to detail is important, and full understanding of the method is required.

Action Potentials↗
PubMed1988

Epidural lipomatosis.

The authors report six new cases of epidural lipomatosis--a rarely described entity characterized by increased extradural fat within the spinal canal causing compression of the spinal cord and neurologic deficits. Five of the six patients had a history of chronic steroid use. Myelography of the thoracic spine, followed by computed tomography (CT), was performed in five patients, and magnetic resonance (MR) imaging was done in three. Myelographic findings were abnormal in three patients and normal in two, compared with those of postmyelography CT, which revealed increased accumulation of extradural fat in all five patients. In the three patients in whom it was performed, MR imaging also showed the increased spinal canal fat. Four patients underwent surgery, which revealed an increased amount of histologically normal, unencapsulated fat in all cases. The diagnosis of epidural lipomatosis should be based on a combination of clinical, imaging, surgical, and histologic findings. If the clinical suspicion is high, even if results of myelography are normal, further evaluation with post-myelography CT or MR imaging should be considered.

Adult↗
PubMed1985

"Reverse" superficial temporal artery-middle cerebral artery bypass.

A new technical variant on the superficial temporal artery-middle cerebral artery anastomosis was performed in a patient with occlusions of both the left internal and external carotid arteries and persistent ischemic symptomatology. Instead of anastomosing the proximal segment of the superficial temporal artery to the middle cerebral artery as is conventionally done, the distal segment of the superficial temporal artery was anastomosed to a cortical branch of the left middle cerebral artery. Reconstituted flow of the left superficial temporal artery via right superficial temporal artery collateral branches proved adequate to relieve the patient's ischemic episodes. "Reverse" superficial temporal artery-middle cerebral artery anastomosis should be considered in those cases where occlusive disease of the external carotid circulation renders conventional bypass procedures ineffective in the treatment of ischemic symptomatology.

Arterial Occlusive Diseases↗