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Robert L. Tiel and David G. Kline

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Daniel H. Kim, Judith A. Murovic, Robert L. Tiel, Gregory Moes and David G. Kline

Object. This is a retrospective review of 397 benign and malignant peripheral neural sheath tumors (PNSTs) that were surgically treated between 1969 and 1999 at the Louisiana State University Health Sciences Center (LSUHSC). The surgical techniques and adjunctive treatments are presented, the tumors are classified with respect to type and prevalence at each neuroanatomical location, and the management of malignant PNSTs is reviewed.

Methods. There were 361 benign PNSTs (91%). One hundred forty-one benign lesions were brachial plexus tumors: 54 schwannomas (38%) and 87 neurofibromas (62%), of which 55 (63%) were solitary neurofibromas and 32 (37%) were neurofibromatosis Type 1 (NF1)—associated neurofibromas. Among the brachial plexus lesions supraclavicular tumors predominated with 37 (69%) of 54 schwannomas; 34 (62%) of 55 solitary neurofibromas; and 19 (59%) of 32 NF1-associated neurofibromas. One hundred ten upper-extremity benign PNSTs consisted of 32 schwannomas (29%) and 78 neurofibromas (71%), of which 45 (58%) were sporadic neurofibromas and 33 (42%) were NF1-associated neurofibromas. Twenty-five benign PNSTs were removed from the pelvic plexus. Lower-extremity PNSTs included 32 schwannomas (38%) and 53 neurofibromas (62%), of which 31 were solitary neurofibromas and 22 were NF1-associated neurofibromas.

There were 36 malignant PNSTs: 28 neurogenic sarcomas and eight other sarcomas (fibro-, spindle cell, synovial, and perineurial sarcomas).

Conclusions. The majority of tumors were benign PNSTs from the brachial plexus region. Most of the benign PNSTs in all locations were neurofibromas, with sporadic neurofibromas predominating. Similar numbers of schwannomas were found in the upper and lower extremities, whereas neurofibromas were more prevalent in the upper extremities. Despite aggressive limb-ablation or limb-sparing surgery plus adjunctive therapy, malignant PNSTs continue to be associated with high morbidity and mortality rates.

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Daniel H. Kim, Judith A. Murovic, Robert L. Tiel, Gregory Moes and David G. Kline

Object. This is a retrospective review of 146 surgically treated benign and malignant peripheral non—neural sheath tumors (PNNSTs). Tumor classifications with patient numbers, locations of benign PNNSTs, and surgical techniques and adjunctive treatments are presented. The results of a literature review regarding tumor frequencies are presented.

Methods. One hundred forty-six patients with 111 benign and 35 malignant PNNSTs were treated between 1969 and 1999 at the Louisiana State University Health Sciences Center (LSUHSC). The benign tumors included 33 ganglion cysts, 16 cases of localized hypertrophic neuropathy, 12 lipomas, 12 tumors of vascular origin, and 11 desmoid tumors. There were four each of lipofibrohamartomas, myositis ossificans, osteochondromas, and ganglioneuromas; two each of meningiomas, cystic hygromas, myoblastoma or granular cell tumors, triton tumors, and lymphangiomas; and one epidermoid cyst. The locations of benign PNNSTs were the following: 33 in the brachial plexus region, 39 in an upper extremity, one in the pelvic plexus, and 38 in a lower extremity.

The malignant PNNSTs included 35 surgically treated carcinomas, 15 of which originated in the breast and nine in the lung. There were two melanomas metastatic to nerve and one tumor each that had metastasized from the bladder, rectum, skin, head and neck, and thyroid, and from a primary Ewing sarcoma. There was a single lymphoma that had metastasized to the radial nerve and one chordoma and one osteosarcoma, each of which had metastasized to the brachial plexus.

Conclusions. There were more benign PNNSTs than malignant ones. Benign tumors were relatively equally distributed in the brachial plexus region and upper and lower extremities, with the exception of the pelvic plexus, which had only one tumor.

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Sunit Das, Aruna Ganju, Robert L. Tiel and David G. Kline

✓Tumors of the brachial plexus are relatively rare and present a clinical challenge for the neurosurgeon. The management of these tumors therefore requires not only an understanding of the complex anatomy of the brachial plexus but also an appreciation of the appropriate surgical approach to the various tumors that may be encountered. Over a 30-year period (1969–1999), 226 patients with brachial plexus tumors were evaluated and surgically treated by the senior authors (R.L.T., D.G.K.). In the present paper they review the most common benign and malignant brachial plexus tumors and discuss management and surgical principles established through their experience at the Louisiana State University Health Sciences Center.

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Daniel H. Kim, Andrew C. Kam, Padmavathi Chandika, Robert L. Tiel and David G. Kline

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.

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Thomas Kretschmer, Doan H. Nguyen, Roger W. Beuerman, Leo T. Happel, John D. England, Robert L. Tiel and David G. Kline

Object. Severe nerve injury induces the formation of a neuroma. Some neuromas cause excruciating pain. Overexpression of Na+ channels leads to hyperexcitability and painful phenomena. Ankyrin G, a multifunctional transmembrane protein of the axolemma, might be a key protein in neuroma formation because it binds Na+ channels in the initial segments of a regenerating axon and links with neuronal cell adhesion molecules. The authors wanted to determine if ankyrin G could be detected in neuroma, and if present, whether there would be differences in distribution between nonpainful neuromas, painful neuromas, and normal nerve.

Methods. First, frozen sections of nine nerve specimens obtained from six patients (six nonpainful neuromas, one painful neuroma, and two normal nerves) were immunocytochemically screened for ankyrin G by using confocal laser scanning microscopy. Second, specimens from 29 patients (seven painful neuromas, 15 nonpainful neuromas, and seven normal nerves) were examined using immunoblot analysis for their ankyrin G content. Western blot analysis detected ankyrin G, which was visualized by applying the enhanced chemiluminescence technique. Computerized densitometry was used to quantitate ankyrin G expression by comparing band intensities. Normal nerve served as control. Neurofilament was used as a marker for nerve tissue content.

Ankyrin G could be detected and was found to be increased in neuromas. The mean band intensity values were 1838 for painful neuromas, 1166 for nonpainful neuromas, and 411 for normal nerves. In two cases the authors were able to compare specimens of painful neuroma and normal nerve from the same patient. The painful neuromas exhibited considerably higher levels of ankyrin G. Painful neuroma and normal nerve densitometry values were 499 and 165, respectively, for one patient, and 4254 and 821, respectively, for the other patient. Painful neuromas were also found to have higher neurofilament values than nonpainful neuromas.

Conclusions. Altered regulation of ankyrin G after nerve injury may lead to hyperexcitability and painful phenomena via clustering of Na+ channels. A propensity to overexpress ankyrin G after peripheral nerve trauma may turn out to be a factor in the development of painful neuromas and neuropathic pain. The relevant literature regarding the importance of ankyrin G for nerve regeneration and nerve membrane remodeling is reviewed.

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Daniel H. Kim, Andrew C. Kam, Padmavathi Chandika, Robert L. Tiel and David G. Kline

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 ≥ 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.

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Robert J. Spinner, John L. D. Atkinson, Bernd W. Scheithauer, Michael G. Rock, Rolfe Birch, Thomas A. Kim, Michel Kliot, David G. Kline and Robert L. Tiel

Object. The peroneal nerve is the most common site of intraneural ganglia. The neurological deficit associated with these cysts is often severe and the operation to eradicate them is difficult. The aims of this multicenter study were to collate the authors' experience with a relatively rare lesion and to improve clinical outcomes by better understanding its controversial pathogenesis.

Methods. Part I of this paper offers a description of 24 patients with peroneal intraneural ganglia who were treated by surgeons aware of the importance of the peroneal nerve's articular branch. Part II offers a description of three more patients who were seen after earlier operations in which the ganglion was excised, but the articular branch was not identified (all reportedly gross-total resections). Twenty-six of the 27 patients presented with clinical, electrophysiological, and imaging evidence of a common peroneal nerve (CPN) lesion, predominantly affecting the deep peroneal nerve (DPN) division, and one patient presented with a painful mass of the CPN that was not accompanied by a neurological deficit.

In all 24 patients in Part I there was magnetic resonance (MR) imaging evidence of a connection between the cyst and the superior tibiofibular joint, including one patient in whom high-resolution (3-tesla) MR neurography demonstrated the pathological articular branch itself. At the operation, the communication proved to extend through the articular branch of the CPN in all cases. The operation consisted of drainage of the cyst and ligation of the articular branch. At a minimum follow-up period of 1 year, these patients experienced significant improvements in their neuropathic pain, but only mild improvements in their functional deficits. In none of the 24 patients was there evidence of an intraneural recurrence. In three patients, however, extraneural ganglia developed: two patients with symptoms subsequently underwent resection of the superior tibiofibular joint without further recurrence and one patient with no symptoms was followed clinically after the recurrence was detected incidentally on 1-year postoperative imaging. As predicted, in Part II all three patients in whom the articular branch had not been ligated experienced early intraneural recurrence; both postoperative MR images and original studies, which were retrospectively examined, demonstrated a connection with the superior tibiofibular joint.

Conclusions. The clinical presentation, electrical studies, imaging characteristics, and operative observations regarding peroneal intraneural ganglia are predictable. Treatment must address the underlying pathoanatomy and should include decompression of the cyst and ligation of the articular branch of the nerve. To avoid extraneural recurrence, resection of the superior tibiofibular joint may also be necessary, but indications for this additional procedure need to be defined. These recommendations are based on the authors' belief that intraneural peroneal ganglia arise from the superior tibiofibular joint and are connected to it by the articular branch.