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Ho-Yeol Zhang, Issada Thongtrangan, Raju S. V. Balabhadra, Judith A. Murovic and Daniel H. Kim

The surgical management of sacral tumors requires partial or total sacrectomy and spinopelvic reconstruction. These lesions present a great surgical challenge, because most spine surgeons are unfamiliar with the techniques required for these procedures. The authors describe a step-by-step operative technique and provide several illustrations.

Total sacrectomy is performed by sequential anterior and posterior approaches that involve a rectus abdominis pull-through pedicle flap reconstruction. The anterior procedure is an intraperitoneal approach used to expose the anterior aspect of the tumor, to ligate the main tumor vessels, and to conduct an anterior partial sacrectomy. After this, the rectus abdominis myocutaneous flap, based on the inferior epigastric vessel, is prepared, and a posterior sacrectomy is performed, dividing all sacral nerve roots in the thecal sac. After complete en bloc extirpation of the sacrum with tumor, spinopelvic reconstruction and closure with a myocutaneous flap are performed. Spinopelvic reconstruction is undertaken using a modified Galveston technique or double iliac screw fixation combined with posterior lumbar segmental fixation. These provide a long lever arm within the ilium to counteract the forces exerted by the lumbar spine.

Understanding the nature of the disease as well as the biomechanics of the lumbosacral pelvic area and spinopelvic fixation will help surgeons select the appropriate treatment for sacral tumors.

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Dosang Cho, Kriangsak Saetia, Sangkook Lee, David G. Kline and Daniel H. Kim

Object

This study analyzes 84 cases of peroneal nerve injuries associated with sports-related knee injuries and their surgical outcome and management.

Methods

The authors retrospectively reviewed the cases of peroneal nerve injury associated with sports between the years 1970 and 2010. Each patient was evaluated for injury mechanism, preoperative neurological status, electrophysiological studies, lesion type, and operative technique (neurolysis and graft repair). Preoperative status of injury was evaluated by using a grading system published by the senior authors. All lesions in continuity had intraoperative nerve action potential recordings.

Results

Eighty-four (approximately 18%) of 448 cases of peroneal nerve injury were found to be sports related, which included skiing (42 cases), football (23 cases), soccer (8 cases), basketball (6 cases), ice hockey (2 cases), track (2 cases) and volleyball (1 case). Of these 84 cases, 48 were identified as not having fracture/dislocation and 36 cases were identified with fracture/dislocation for surgical interventions. Good functional outcomes from graft repair of graft length < 6 cm (70%) and neurolysis (85%) in low-intensity peroneal nerve injuries associated with sports were obtained. Recovery from graft repair of graft length between 6 and 12 cm (43%) was good and measured between Grades 3 and 4. However, recovery from graft repair of graft length between 13 and 24 cm was obtained in only 25% of patients.

Conclusions

Traumatic knee-level peroneal nerve injury due to sports is usually associated with stretch/contusion, which more often requires graft repair. Graft length is the factor to be considered for the prognosis of nerve repair.

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Sangkook Lee, Kriangsak Saetia, Suparna Saha, David G. Kline and Daniel H. Kim

Object

The aim of this retrospective study was to present and investigate axillary nerve injuries associated with sports.

Methods

This study retrospectively reviewed 26 axillary nerve injuries associated with sports between the years 1985 and 2010. Preoperative status of the axillary nerve was evaluated by using the Louisiana State University Health Science Center (LSUHSC) grading system published by the senior authors. Intraoperative nerve action potential recordings were performed to check nerve conduction and assess the possibility of resection. Neurolysis, suture, and nerve grafts were used for the surgical repair of the injured nerves. In 9 patients with partial loss of function and 3 with complete loss, neurolysis based on nerve action potential recordings was the primary treatment. Two patients with complete loss of function were treated with resection and suturing and 12 with resection and nerve grafting. The minimum follow-up period was 16 months (mean 20 months).

Results

The injuries were associated with the following sports: skiing (12 cases), football (5), rugby (2), baseball (2), ice hockey (2), soccer (1), weightlifting (1), and wrestling (1). Functional recovery was excellent. Neurolysis was performed in 9 cases, resulting in an average functional recovery of LSUHSC Grade 4.2. Recovery with graft repairs averaged LSUHSC Grade 3 or better in 11 of 12 cases

Conclusions

Surgical repair can restore useful deltoid function in patients with sports-associated axillary nerve injuries, even in cases of severe stretch–contusion injury.

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Benjamin D. Elder, Krishanthan Vigneswaran, Kyriacos A. Athanasiou and Daniel H. Kim

Object

Tissue engineering appears to be a promising strategy for articular cartilage regeneration as a treatment for facet joint arthritis. Prior to the commencement of tissue engineering approaches, design criteria must be established to determine the required functional properties of the replacement tissue. As characterization of the functional properties of facet joint cartilage has not been performed previously, the objective of this study was to determine the biomechanical, biochemical, and histological properties of facet joint cartilage.

Methods

The in vitro testing was conducted using 4 lumbar spinal segments obtained from skeletally mature canines. In each specimen, articular cartilage was obtained from the superior surface of the L3–4 and L4–5 facet joints. Creep indentation was used to determine the compressive biomechanical properties, while uniaxial tensile testing yielded the Young modulus and ultimate tensile strength of the tissue. Additionally, biochemical assessments included determinations of cellularity, glycosaminoglycan (GAG) content, and collagen content, as well as enzymelinked immunosorbent assays for collagen I and II production. Finally, histological characterization included H & E staining, as well as staining for collagen and GAG distributions.

Results

The means ± standard deviation values were determined. There were no differences between the 2 spinal levels for any of the assessed properties. Averaged over both levels, the thickness was 0.49 ± 0.10 mm and the hydration was 74.7 ± 1.7%. Additionally, the cells/wet weight (WW) ratio was 6.26 ± 2.66 × 104 cells/mg and the cells/dry weight (DW) ratio was 2.51 ± 1.21 × 105 cells/mg. The GAG/WW was 0.038 ± 0.013 and the GAG/ DW was 0.149 ± 0.049 mg/mg, while the collagen/WW was 0.168 ± 0.026 and collagen/DW was 0.681 ± 0.154 mg/ mg. Finally, the aggregate modulus was 554 ± 133 kPa, the Young modulus was 10.08 ± 8.07 MPa, and the ultimate tensile strength was 4.44 ± 2.40 MPa.

Conclusions

To the best of the authors' knowledge, this study is the first to provide a functional characterization of facet joint articular cartilage, thus providing design criteria for future tissue engineering studies.

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Daniel H. Kim, Yong-Jun Cho, Robert L. Tiel and David G. Kline

Object. Outcomes of 1019 brachial plexus lesions in patients who underwent surgery at Louisiana State University Health Sciences Center during a 30-year period are reviewed in this paper to provide management guidelines.

Methods. Causes of brachial plexus lesions included 509 stretches/contusions (50%), 161 plexus tumors (16%), 160 thoracic outlet syndromes (TOSs, 16%), 118 gunshot wounds (12%), and 71 lacerations (7%). Many features of clinical presentation, including prior treatment, patient's neurological status, results of electrophysiological studies, intraoperative findings, and postoperative level of function, were studied. The minimum follow-up period was 18 months and the mean follow-up period was 42 months. Repairs were best for injuries located at the C-5, C-6, and C-7 levels, the upper and middle trunk, the lateral cord to the musculocutaneous nerve, and the median and posterior cords to the axillary and radial nerves. Conversely, results were poor for injuries at the C-8 and T-1 levels, and for lower trunk and medial cord lesions, with the exception of injuries of the medial cord to the median nerve. Outcomes were most favorable when patients were carefully evaluated and selected for surgery, although variables such as lesion type, location, and severity, as well as time since injury also affected outcome. This was true also of TOSs and tumors arising from the plexus, especially if they had not been surgically treated previously.

Conclusions. Surgical exploration and repair of brachial plexus lesions is technically feasible and favorable outcomes can be achieved if patients are thoroughly evaluated and appropriately selected.

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Daniel H. Kim, Kisoo Han, Robert L. Tiel, Judith A. Murovic and David G. Kline

Object. In this article the authors present a retrospective analysis of 654 surgical outcomes in patients with ulnar nerve entrapments, injuries, and tumors during a 30-year period.

Methods. Data were gathered between 1968 and 1998 at Louisiana State University Health Sciences Center. Mechanisms of injuries or lesions included 460 entrapments at the elbow level (70%), 76 lacerations (12%), 52 stretches/contusions (8%), 34 fractures/dislocations (5%), 12 gunshot wounds (2%), two injection-induced injuries (0.3%), and 13 nerve sheath tumors (2%).

In cases of entrapment, direct operative recordings uniformly demonstrated a slowing of conduction at the elbow, even in cases in which preoperative noninvasive studies had been nondiagnostic. Intraoperative electrical “inching” studies also demonstrated significant conduction abnormalities that lie just proximal to and through the olecranon notch rather than distal, beneath the flexor carpi ulnaris muscle. There were only eight exceptions to this. Lesions not in continuity due to the injury required primary or secondary end-to-end sutures or graft repair. Aided by intraoperative nerve action potential recording, lesions in continuity received either external or internal neurolysis and split repair or resection followed by end-to-end suture or graft repair. Functional recoveries of Grade 3 or better were seen in 81 (92%) of 88 patients who underwent neurolysis, 42 (72%) of 58 patients who received suture repair, and 24 (67%) of 36 patients who received graft repair. Nevertheless, fewer Grade 4 or 5 recoveries were reached than those seen in patients with radial or median nerve injuries. Nerve sheath tumors were resected with preservation of preoperative function in five of seven patients.

Conclusions. Although difficult to obtain, useful functional recovery can be achieved with proper surgical management of ulnar nerve entrapments and injuries.

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Sung Woo Roh, Daniel H. Kim, Alberto C. Cardoso and Richard G. Fessler

Although the anterior approach is more commonly performed for the treatment of cervical disc disease, the posterior approach has distinct advantages in selected cases of foraminal stenosis and posterolateral disc herniation. The authors performed cervical key hole foraminotomies using a microendoscopic discectomy (MED) system in four cadaveric cervical spine specimens to evaluate this minimally invasive surgical approach for cervical disc diseases. The amount of bone decompression achieved by using the MED system was compared with that achieved by using the open foraminotomy procedure in each cadaveric specimen. Three noncontiguous cervical nerve roots were selected between C-3 and C-8 in each specimen and were decompressed using the MED system on one side and using the open foraminotomy procedure on the contralateral side. Postoperative computerized tomography (CT) myelography showed that adequate bone decompression was achieved by using either the MED or open procedure in all specimens. Postoperatively, open dissection was performed to confirm and compare the amount of decompression in both the MED and open procedures. The laminotomy size (vertical and transverse diameter), the length of decompressed nerve root, and the proportion of removed facet joint were measured on every operative level. The average vertical diameter of laminotomy area and the percentage of facet removed were significantly greater in the MED procedure than the open procedure (p < 0.05). The transverse diameter of the laminotomy area and the average decompressed root length were not significantly different between MED and open surgery. The authors conclude that endoscopic cervical foraminotomy using the MED system is a feasible procedure and may be clinically applicable in the treatment of foraminal stenosis and laterally located cervical disc herniation.

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Issada Thongtrangan, Raju S. V. Balabhadra, Hoang Le, Jon Park and Daniel H. Kim

Object

The authors report their clinical experience with expandable cages used to stabilize the spine after verte-brectomy. The objectives of surgical treatment for spine tumors include a decrease in pain, decompression of the neural elements, mechanical stabilization of the spine, and wide resection to gain local control of certain primary tumors. Most of the lesions occur in the anterior column or vertebral body (VB). Anterior column defects following resection of VBs require surgical restoration of anterior column support. Recently, various expandable cages have been developed and used clinically for VB replacement (VBR).

Methods

Between January 2001 and June 2003, the authors treated 15 patients who presented with primary spinal tumors and metastatic lesions from remote sites. All patients underwent vertebrectomy, VBR with an expandable cage, and anterior instrumentation with or without posterior instrumentation, depending on the stability of the involved segment. The correction of kyphotic angle was achieved at an average of 20°. Pain scores according to the visual analog scale decreased from 8.4 to 5.2 at the last follow-up review. Patients whose Frankel neurological grade was below D attained at least a one-grade improvement after surgery. All patients achieved immediate stability postsurgery and there were no significant complications related to the expandable cage.

Conclusions

The advantage of the expandable cage is that it is easy to use because it permits optimal fit and correction of the deformity by in vivo expansion of the device. These results are promising, but long-term follow up is required.

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Daniel H. Kim, Seán E. Connolly, Joseph T. Gillespie, Rand M. Voorhies and David G. Kline

✓ 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 × 20-mm grafts in one leg and by 4 × 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 × 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.

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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.