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Biomedical subjects

D G Kline

Publications and source records attributed to D G Kline.

At least 55 records · Page 3Linked to original sources
PubMed1993

Penfield Lecture. A quarter century's experience with intraoperative nerve action potential recording.

The rationale, basic considerations, and technique of intraoperative nerve action potential (NAP) recording have been reviewed. Experience using this technique in several thousand patients over a 25 year period has been summarized. The most frequent serious nerve injury is one that leaves it in continuity. Resection of such a lesion that is regenerating does the patient a great disservice as does exploration without repair of one with little or no potential for useful spontaneous recovery. The frequency of lesions in continuity as well as the difficulties in evaluating them in the early months by electromyography let alone by surgical inspection has led to the development of intraoperative NAP recording. Where neurolysis was based on a recordable NAP across a lesion in continuity, 93% recovered good function. Where resection of the lesion was based on absence of an NAP, the injury was, without exception, neurotmetic and/or one with poor potential for useful recovery without repair. Some lesions had an NAP across their lesion but a portion of the cross-sectional area appeared more seriously injured. By use of NAP recordings, a split repair was done and usually with good results.

Action Potentials↗
PubMed1993

Sciatic nerve regeneration across gaps within collagen chambers: the influence of epidermal growth factor.

The effects of Epidermal Growth Factor (EGF) on axonal regeneration of a sectioned sciatic nerve within collagen tubes were investigated in 15 rats. Following baseline electrophysiologic assessment, bilateral 7-mm nerve gaps were created and repaired by interposition of collagen tubes, into which EGF (left side) or type I collagen (right side) was instilled. After 4 or 8 weeks, axonal regeneration, measured by electrophysiologic and histologic means, was identical for the EGF and control legs. The conclusion is that EGF does not influence nerve regeneration within a collagen chamber.

Action Potentials↗
PubMed1993

Comparison of macropore, semipermeable, and nonpermeable collagen conduits in nerve repair.

Twelve rabbits were used to study functional nerve regeneration through macropore, semipermeable, and nonpermeable collagen conduits. Each animal underwent a 10-mm bilateral resection of posterior tibial nerve. Lesions were repaired with a macropore collagen tube in one leg, and with a semipermeable or a nonpermeable collagen tube contralaterally. Functional nerve regeneration was evaluated at 6 and 12 weeks post-repair periods. Functional recovery was assessed by electrophysiologic analysis of nerve conduction velocity, amplitude of nerve action potential, amplitude and area of muscle action potential, and by quantitative and qualitative histologic analysis of myelinated nerve fibers from the distal nerve stumps. The macropore-collagen-tube group showed significantly greater functional recoveries than semipermeable or nonpermeable collagen-tube groups, based on electrophysiologic and histologic analyses.

Animals↗
PubMed1993

Extracranial spinal accessory nerve injury.

Eighty-three consecutive patients with extracranial accessory nerve injury seen over a 12-year period are reviewed. The most common etiology was iatrogenic injury to the nerve at the time of previous surgery. Such operations were usually minor in nature and often related to lymph node or benign tumor removal. Examination usually distinguished winging due to trapezius weakness from that of serratus anterior palsy. Trapezius weakness was seen in all cases. Sternocleidomastoid weakness was unusual. Patients with accessory palsy were evaluated by both clinical and electromyographic studies. Patients who exhibited no clinical or electrical evidence of regeneration were operated on (44 cases). Based on intraoperative nerve action potential studies, 8 lesions in continuity had neurolysis alone. Resection with repair either by end-to-end suture or by grafts was necessary in 31 cases. One case had suture removed from nerve, two had nerve placed into target muscle, and two had more proximal neurotization. Function was usually improved in both operative and nonoperative patients. Related anatomy is discussed.

Accessory Nerve↗
PubMed1993

Posterior subscapular approach to the brachial plexus. Report of 102 patients.

A 15-year operative experience with 105 posterior subscapular approaches to the brachial plexus in 102 patients is presented. The procedure is indicated in carefully selected cases, especially where the proximal portions of lower spinal nerves are involved. Its main advantage is proximal exposure of the plexus spinal nerves, particularly at an intraforaminal level. The indications in this series were thoracic outlet syndrome (TOS) in 51 carefully selected procedures, brachial plexus tumor involving proximal roots in 22 patients, post-irradiation brachial plexopathy in 14 cases, and proximal traumatic brachial plexus palsy in 18 patients. Thoracic outlet syndrome associated with neurological loss, recurrent TOS after a prior operation, or proximal brachial plexus surgical lesions involving the spinal nerve(s), especially at an intraforaminal level, can be approached advantageously by such a posterior subscapular approach. The technique should also be considered when prior operation, trauma, or irradiation to the neck or anterior chest wall make a posterior exploration of the plexus easier than an anterior one. Anterior exposure of the plexus is the preferable approach for the majority of lesions needing an operation, but the posterior subscapular procedure can be useful in well-selected cases.

Adult↗
PubMed1992

Intraforaminal repair of plexus spinal nerves by a posterior approach: an experimental study.

Many spinal nerve roots injured due to stretch or other types of lesions are not reparable. Some spinal nerves might be repaired if they could be exposed in their intraforaminal course. A posterior subscapular approach for a more lateral exposure of the brachial plexus was combined with a facetectomy to expose intraforaminal nerves in a series of Macaca rhesus monkeys. This approach exposed a 6- to 10-mm segment of spinal nerve not approachable by a more classic anterior operation. Sural grafts were placed from the dural exit of the spinal nerves to the cord level of the plexus. Nine surviving animals were followed for 36 to 54 months and observed for clinical evidence of return of function. In each animal at least one electromyogram (EMG) was performed. The plexus was then re-exposed and intraoperative nerve action potentials were recorded across graft sites. Evoked muscle action potential and cortical potentials were recorded in six animals. Despite the proximal level of repair, adequate regeneration was shown by clinical, electrical, and histological studies. Functional return was best to the supraspinatus and biceps muscles and to wrist and finger flexors. Clinical recovery was present, but less effective, for deltoid, wrist, and finger extensors and intrinsic muscles of the hand, despite evidence on EMG of reinnervation. Recovery of the infraspinatus muscle was poor. Nerve action potentials could be recorded across each graft site. Reinnervational activity was recorded by EMG and evoked muscle action potential studies in most of the muscles studied, despite the persistence of some denervational changes 3 years or more after injury and repair. Histological studies confirmed the presence of a large number of axons of moderate size and myelination even at the forearm level.

Action Potentials↗
PubMed1992

Indications for peripheral nerve and brachial plexus surgery.

Management of peripheral nerve injuries differs depending on the mechanism of injury. 1. If a nerve has been sharply and completely transected, it should be acutely repaired, especially if proximally located. 2. If a nerve has been bluntly divided and the stumps are found to be bruised, they should be tacked to adjacent planes. A secondary repair at 2 to 4 weeks is then recommended. 3. With closed injury in which the nerve is most likely still in continuity, the patient should be followed clinically and electrically for 2 to 5 months, depending on the nerve involved and the mechanism of injury. If there is no reversal of the proximal portion of the neurologic deficit by that time, surgical exploration should be done. Use of intraoperative NAP testing is important in this large category of injuries. 4. Injection and electrical injuries to a nerve are two special categories of lesions in continuity and require a highly specialized and individualized treatment dependent on the degree of deficit and severity of pain. 5. Pain unresponsive to medical treatment may also be an indication for surgery on a peripheral nerve, especially if the injured nerve needs to be repaired because of persistent neurologic loss. 6. Management of brachial plexus injuries is somewhat different. Function of each element of the plexus has to be analyzed separately. Several clinical, electrical, and radiologic findings may provide important information about how proximal the lesion is. 7. Missile wounds usually leave the nerve in continuity. Initial management is surgically conservative. Nonetheless, many of these lesions will subsequently require resection based on NAP recordings. 8. Management of obstetric brachial plexus palsy is controversial. We recommend initial conservative management, with observation much longer (9 to 12 months) than for other stretch injuries occurring in adults. With this approach, some but not many of such injuries will still need repair.

Brachial Plexus↗
PubMed1991

Schwannoma of the brachial plexus mimicking an apical lung tumor.

Primary tumors of the brachial plexus are unusual. We describe a patient with a large schwannoma of the lower trunk of the brachial plexus that had the radiologic appearance of an apical lung mass. Use of a posterior subscapular approach as well as intraoperative nerve action potential recording permitted resection with spared function.

Adult↗
PubMed1991

Electrophysiological studies of various graft lengths and lesion lengths in repair of nerve gaps in primates.

Electrophysiological studies were used to evaluate neurological recovery in 14 rhesus monkeys with different nerve lesion lengths and graft lengths. After exposure of both sciatic nerves in each animal, baseline evoked nerve action potentials, muscle action potentials, and muscle strength values were determined for the posterior tibial nerves. Each nerve was then crushed over a measured distance. Three weeks later, the crushed segments were resected and the defects repaired with sural nerve grafts. In seven animals, 20-mm resection sites were repaired by 4 x 20-mm grafts in one leg and by 4 x 40-mm grafts contralaterally. In the other seven animals, the lengths of resection sites were 10 mm in one leg and 30 mm contralaterally; both nerve defects in these animals were repaired by 4 x 30-mm grafts. Electrophysiological studies were repeated at one interval of either 4, 7, or 12 months after repair. Postoperative electrophysiological values were compared to baseline values and described by the mean values and by percent recovery. Muscle strength recovery was significantly better in limbs with short lesions. In animals with identical lesion lengths, lesions repaired with shorter grafts (the same length as the defect) did significantly worse than did lesions repaired with longer grafts. This may suggest that any degree of tension at the graft repair site has a deleterious effect on functional nerve regeneration. Nevertheless, it was generally found that nerve lesion length had the greatest negative effect on functional nerve regeneration.

Action Potentials↗
PubMed1991

Neuromuscular hamartoma (benign "triton" tumor) of the brachial plexus. Case report.

Neuromuscular hamartoma (choristoma) or benign "triton" tumor is a very rare peripheral-nerve tumor composed of mature nerve fibers and well-differentiated striated muscle fibers. Only seven cases have been reported in the literature. A new case of this rare entity is described in a 36-year-old white woman with a recurrent left supraclavicular mass in the brachial plexus area. Unlike the previous cases, this patient had continued to have proliferation of her tumor since childhood, requiring total resection in adulthood. It is concluded that total resection of these tumors should be attempted at initial diagnosis. The histogenesis of these tumors remains unclear. They may represent proliferation of neuroectodermal-derived or limb mesodermal tissue in the elements of a peripheral nerve.

Adult↗
PubMed1990

Surgical repair of peripheral nerve injury.

Magnification, use of fine interfascicular grafts for repair, and development of intraoperative electrophysiologic measurements of function have had a substantial impact on this field in the last 10 to 20 years. Basic surgical principles established during and since World War II remain the foundation for surgical repair of peripheral nerve injury but have been complemented nicely by these more recent advances. Selection of patients for surgery, as well as the timing of such, has been reviewed with emphasis on the differences between suspected transections and lesions in continuity, as well as comments on serious peripheral entrapments and tumors affecting nerve. The importance of not only preoperative electromyographic studies but also the intraoperative use of stimulation and stimulation and recording of nerve action potentials (NAPs) for lesions in continuity has been stressed. Operative techniques such as neurolysis, NAP recordings, suture, split repair, and interfascicular graft repair have been reviewed and some commentary on results provided. There has been a gradual evolution of centers in this country and abroad for care of the more serious surgical nerve problems. It is anticipated that in the future, such centers will be able to provide improved data concerning results with civilian nerve injuries.

Action Potentials↗
PubMed1990

Initial evaluation of variable graft lengths and lesion lengths in the repair of nerve gaps.

This experiment evaluated the electrical and histologic differences between two groups of rats, one of which underwent same-length bilateral resection of posterior tibial nerves prior to being repaired with grafts of different lengths, while the other group underwent different-length resections with same-length graft repair. In this rat model, 18 animals were used and divided into two groups. The first group of animals underwent bilateral resection of 8-mm segments of posterior tibial nerve. To repair these nerves, one leg received two 8-mm sural nerve grafts (Group A), while the other leg received two 16-mm sural nerve grafts (Group B). The second group of rats underwent posterior tibial nerve resections of 8 mm and 16 mm, respectively. The leg with the 8 mm of posterior tibial nerve resected, received two side-by-side 16-mm sural nerve grafts (Group C); the other leg with 16 mm resected, received two 16-mm sural nerve grafts (Group D). Electrophysiologic comparison of nerve conduction velocity for Groups A and B showed a significant difference (p less than 0.05), as did the same comparison for Groups C and D (p less than 0.05). Histologic studies showed that Groups A and D had marked extrafascicular escape of the regenerating nerve axons, disorganizational growth of minifascicles, and loss of integrity of the donor fascicles, while Groups B and C had very minimal extrafascicular escape of regenerating axons.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1990

Peri-epineurial tissue to supplement laser welding of nerve.

The principal difficulty with laser repair of nerves has been the inability to provide enough initial tensile strength to prevent separation of nerve ends. In previous experimental studies, dehiscence rates of laser-repaired nerves ranged between 12 to 25% whereas that for conventional epineurial suture repair was 0%. In our study, sciatic nerves of rats were transected bilaterally. Results of anastomosis by conventional epineurial suture on one side were compared with those of tissue welding by the CO2 laser using peri-epineurial sheath as a structural adjunct on the other side. At the time of reexploration at 7, 12, and 16 weeks, there was no dehiscence in nerves of either the laser with peri-epineurial sheath group or the suture repair groups. Electrophysiological and morphometric values after use of peri-epineurial tissue as an adjunct to tissue welding by the CO2 laser were comparable to those of conventional suture repair.

Action Potentials↗
PubMed1990

Posterior interosseous nerve palsies.

One hundred seventy patients with radial nerve disorders were reviewed at the Louisiana State University Medical Center over a 15-year period. Of these, 32 had involvement of the posterior interosseous nerve exclusively. Findings included weak wrist extension with a radial drift, inability to extend the fingers, paralysis of thumb extension, and weak thumb abduction. Causes included entrapment at the arcade of Froshe (14 patients), laceration (6 patients), fracture (6 patients), compression or contusion (3 patients), and loss associated with tumor (3 patients). The ratio of men to women was 2:1, and the right arm was involved twice as often as the left. Preoperative evaluation included physical examination, electrophysiological testing (electromyogram/nerve conduction velocity), and roentgenograms of the elbow and forearm. Of the 30 patients (2 patients had bilateral lesions), 26 underwent operation. In the operative series, all 28 nerves had a function of Grade 3 or more of a possible 5 after 4 years of follow-up. Seventeen had achieved Grade 4/5, and 7 had obtained Grade 5/5. At operation, 23 nerves were found to be in continuity. Fourteen lesions of nerves in continuity were associated with entrapment and, not unexpectedly, transmitted a nerve action potential with slowed conduction and low amplitude across the lesion. Four nerves in continuity that had lesions caused by injury had nerve action potentials and were treated by neurolysis, and another 4 had no nerve action potentials and were treated by graft or suture repair. Five injured nerves were not in continuity. Two could be repaired by end-to-end suture, and 3 required graft repair. A large ganglion cyst involving the posterior interosseous nerve was also resected.

Action Potentials↗
PubMed1989

Is limb-sparing surgery applicable to neurogenic sarcomas of the extremities?

The presentation, treatment, and outcome of 12 patients with high-grade neurogenic sarcoma (NS) of the extremity were compared with those of 21 patients with high-grade extremity soft-tissue sarcoma of nonneural origin in a retrospective study from January 1976 to January 1988. Pain and neurologic deficit were more common in the NS group. Limb-sparing surgery was carried out with equal frequency in both groups. Local recurrence was six times more frequent in the NS group at three-year follow-up (59% vs 10%). Width of resection margin was the dominant prognostic variable bearing on local control after limb-sparing surgery. Anatomic and functional constraints tended to limit resection margin in patients with NS arising from mixed motor-sensory or predominantly motor nerves.

Adult↗