Retropleural thoracotomy. Technical note.

Herniated thoracic discs, unlike their lumbar counterparts, are difficult to read and safely resect using traditional posterior approaches. Historically, the use of a laminectomy for thoracic disc resection has yielded poor clinical outcomes. Posterolateral and anterolateral approaches have become the standard surgical means of treating these lesions. The traditional anterolateral approach, the transpleural thoracotomy, is an extensive procedure that requires direct retraction of the lung, a deep surgical field, and postoperative closed-chest drainage. An alternative to this anterior approach, the retropleural thoracotomy, is described here. This approach provides the shortest direct route to the thoracic spine and leaves the pleura intact. A smaller incision and less retraction than traditional approaches may reduce postoperative pain and pulmonary-related complications. The retropleural thoracotomy is a valuable technique for the neurosurgeon treating thoracic disc disease.

Intramedullary ependymomas: clinical presentation, surgical treatment strategies and prognosis.

Intramedullary ependymomas are rare tumors but comprise the majority of intramedullary glial neoplasms in the adult. These tumors are benign, slow-growing lesions which are optimally treated with gross-total surgical resection without adjuvant therapy. This objective can be attained safely in a majority, of patients. Post-operative functional outcome is related to pre-operative functional status. Hence, early diagnosis, prior to symptomatic progression, is critical to the successful treatment of these tumors. Adjuvant therapy is indicated for the rare malignant or disseminated tumor or following sub-total resection.

Genetic basis of intramedullary spinal cord tumors and therapeutic implications.

The advent of molecular biology has provided tools to delineate genetic mutations that cause disease. Recently, several genetic mutations have been associated with intramedullary spinal cord tumors. Concurrently, advances in micro-neurosurgical techniques have significantly decreased the morbidity of surgical resection. In this review, we describe the current understanding of genetic mutations in sporadic and familial intramedullary spinal cord tumors. The future success of innovative gene therapy protocols may depend upon establishing a cause and effect relationship between these genetic mutations and disease progression. Successful gene therapy will also depend upon increasing the efficiency of gene therapy vector delivery.

Non-neoplastic intramedullary pathology. Diagnostic dilemma: to Bx or not to Bx.

There are several non-neoplastic lesions which may mimic intramedullary spinal cord neoplasm in their radiographic and clinical presentation. These can be classified as either infectious (TB, fungal, bacterial, parasitic, syphilis, CMV, HSV) and non-infectious (sarcoid, MS, myelitis, ADEM, SLE) inflammatory lesions, idiopathic necrotizing myelopathy, unusual vascular lesions (amyloid, infarct, isolated intramedullary vascular lesions) and radiation myelopathy. Although biopsy may be indicated in many cases, the mistaken diagnosis of intramedullary neoplasm can often be eliminated pre-operatively.

The posterior approach to a series of glomus (Type II) intramedullary spinal cord arteriovenous malformations.

OBJECTIVE: Intramedullary spinal cord arteriovenous malformations (AVMs) are comprised of those AVMs which in either glomus or nidal form are found partially or entirely within the substance of the spinal cord. An effort to subdivide these lesions into either glomus Type II or juvenile Type III spinal cord AVMs has underscored the diffuse, unresectable nature of the latter but has done little to suggest a logical management paradigm for the more well-defined, low-flow glomus lesion. METHODS: To address this shortcoming, 15 cases of glomus Type II spinal AVMs were identified from a larger series of a variety of spinal AVMs. Computed tomography, magnetic resonance imaging, and superselective angiography rendered the anatomic diagnosis of these lesions accurate in all cases. All lesions were approached posteriorly via a standard laminectomy, with the goal of total extirpation, and all patients underwent immediate postoperative angiography to verify cure. In the vast majority of cases, patients underwent follow-up imaging to confirm the durability of this cure, and long-term outcome was determined using both a subjective quality of life assay and a functional grading scale. Age, sex, mode of presentation, and radiographic features were subsequently analyzed with respect to functional outcome. RESULTS: Most glomus spinal AVMs presented with a rapid cascade of signs and symptoms (73%), often caused by subarachnoid hemorrhage (60%) and often leading to significant neurological deficits (47%). Initially, 14 of 15 patients (94%) were angiographically cured of their malformations. The remaining patient was neurologically improved after a 90% resection, and follow-up angiography demonstrated that the residual was thrombosed. However, not uncommonly, follow-up angiography and magnetic resonance imaging revealed recurrences, with three of the patients who underwent delayed imaging (23%) demonstrating new draining veins. Fortunately, in each case, the recurrence was asymptomatic. Therefore, the long-term cure rate (mean follow-up, 8.5 yr; range, 1-17 yr) was 80%, with no subsequent bleeding or progression of symptoms. Outcomes were generally good, with six patients (40%) demonstrating objective improvement, eight (53%) being neurologically stable, and one (7%) being worse. Sixty-six percent were independent, 20% required moderate assistance, and 14% remained entirely dependent. There were no deaths. Patients possessing lesions with large direct feeders off the anterior spinal artery and occupying a primarily anterior position in the cord fared somewhat worse, as did those with rapidly progressing symptomatology in the absence of subarachnoid hemorrhage. However, even in those with preserved or improved function, chronic pain was a significant problem, affecting one-third of all patients. Chronic pain was especially common in young women who had presented with significant preoperative pain that responded poorly to all subsequent therapeutic manipulations. CONCLUSION: With careful evaluation of high-quality superselective angiography and the judicious use of preoperative embolization, posterior surgical approaches can deliver results comparable with those achieved for other benign intramedullary lesions in terms of long-term cure (80%), control of symptom progression (100%), and good functional outcome (86%). Despite these results, chronic dysesthetic pain syndromes are not uncommon and continue to present a significant management problem.

Surgical approaches to the thoracolumbar spine.

Surgical treatment of diseases involving the thoracolumbar spine offers a unique challenge to the spine surgeon. Although more familiar posterior techniques are useful for a variety of thoracolumbar problems, the management of disease in this region is often optimized by an anterior approach. Thoracolumbar surgery requires an understanding of the relevant surgical anatomy, the pathologic processes affecting this region, and the relative indications and contraindications for particular operative strategies. It is also essential to be familiar with the management of potential morbidity, methods for avoiding complications, and the selection of particular fusion techniques and instrumentation devices associated with specific operative strategies.

Atlantoaxial degenerative articular cysts.

Cysts associated with spinal joints are not a common cause of neurological symptoms. The authors report a series of five patients with cysts of the atlantodental articulation and review five additional cases from the literature. The patients ranged from 60 to 85 years of age and included three men and seven women. No patient had evidence of rheumatoid arthritis or previous trauma. The cysts caused ventral cervicomedullary compression, did not enhance on magnetic resonance imaging, and were not associated with widening of the anterior atlantodental interval or osseous degeneration of the dens. All patients improved postsurgery. Fusion was required if a transoral procedure was performed. Patients undergoing posterior decompressions were clinically and radiographically stable after operation.

Intramedullary spinal cord metastasis: report of three cases and review of the literature.

BACKGROUND: Intramedullary spinal cord metastasis is rare; but it is being encountered with increasing frequency. Optimal treatment after diagnosis remains controversial. METHODS: In the last 3 years, we have encountered three cases of intramedullary metastasis presenting as focal mass lesions with minimal systemic evidence of cancer. We present our results in these patients and review the literature in an effort to more optimally define both the natural course of this disease, as well as a potential subset of patients who might benefit from more aggressive treatment. RESULTS: With the availability of more sensitive imaging techniques, these tumors are being diagnosed with increasing frequency. Magnetic resonance imaging is sensitive, but nonspecific, in distinguishing intramedullary spinal cord metastases from primary cord tumors. Urgent biopsy is often necessary prior to definitive treatment. Radiation with chemotherapy significantly prolongs survival. Radical subtotal resection may offer additional quality survival, especially in cases of metastatic melanoma with an occult primary. CONCLUSIONS: Regardless of treatment, many patients survive less than 1 year. Intramedullary spinal cord metastasis is a devastating condition, but with appropriate diagnosis and aggressive treatment, selected patients may have substantially increased survival.

Management of spinal epidural hematoma after tissue plasminogen activator. A case report.

STUDY DESIGN: This case report illustrates a patient with a spontaneous epidural hematoma after tissue plasminogen activator therapy who presented 10 days after the incident with a resolving Brown-Sèquard syndrome. OBJECTIVES: The treatment of this patient involves the principles of conservative follow-up directed by an improving examination and an understanding of the pathophysiology of coagulopathy-induced spontaneous epidural bleeds. SUMMARY OF BACKGROUND DATA: The use of tissue plasminogen activator therapy for thrombolysis in patients with early acute myocardial infarction is becoming increasingly routine. Use is limited most significantly by bleeding complications. Recently, several groups have drawn attention to the neurologic complications associated with intracranial hemorrhage after tissue plasminogen activator therapy. Spontaneous spinal epidural hemorrhage has, by comparison, received little attention. The authors report the second case in the literature and the first without a history of antecedent trauma. METHODS: The onset of the painful myelopathy in this patient was missed in the acute setting because of low suspicion. When the diagnosis was made, coadministered heparin had already been discontinued without reversal, and the patient's examination had already improved. Careful follow-up by neurologic examination and magnetic resonance imaging was obtained without spinal angiography being performed. RESULTS: The patient regained his prehemorrhage neurologic status, experienced no further bleeding, and his coronary ischemia remained subclinical. CONCLUSIONS: Spinal epidural hemorrhage secondary to thrombolytic therapy is becoming increasingly common. Urgent surgical decompression is generally warranted to preserve neurologic function. In cases where the deficit is minimal or resolving, a conservative approach may be warranted with magnetic resonance imaging but not angiographic follow-up.

High cervical split cord malformation and neurenteric cyst associated with congenital mirror movements: case report.

A 48-year-old woman with congenital mirror movements of the hands presented with a high cervical split spinal cord malformation and a ventrally located neurenteric cyst. The clinical, radiological, and surgical features are presented. A brief discussion of the literature and embryology pertaining to split cord malformations and mirror movements is included. To our knowledge, this is the first case of radiographically and surgically proven split cord malformation associated with either mirror movements or a neurenteric cyst presenting in an adult.

Surgical management of dumbbell tumors of the cervical spine.

Twelve patients with benign dumbbell tumors of the cervical spine were treated surgically between March 1991 and July 1994. Gross total resection was achieved in 11 patients, using a single-stage modified posterior midline exposure with laminectomy and complete unilateral facetectomy. This exposure provides contiguous intraspinal, foraminal, and extraforaminal access that extends up to 4 cm from the lateral dural margin. The surgical considerations of these tumors, including the surgical technique, potential spinal instability, vertebral artery, and risk of nerve root injury, are presented.

Surgical management of dumbbell and paraspinal tumors of the thoracic and lumbar spine.

The lateral extracavitary approach was used for single-staged tumor resection in 12 patients with complex dumbbell or paraspinal tumors of the thoracic and lumbar spine. Six women and six men (age, 28-72 yr) were treated between August 1990 and January 1994. The tumors included schwannoma (6 patients), malignant meningioma (1 patient), hemangioma (1 patient), chondrosarcoma (1 patient), osteocartilaginous exostosis (1 patient), radiation-induced osteogenic sarcoma (1 patient), and metastatic renal carcinoma (1 patient). Gross total resection was achieved in 11 patients. Radical subtotal removal was performed in the remaining patient, who had a malignant osteogenic sarcoma. Concomitant spinal stabilization with internal fixation and anterior interbody strut grafting was performed on two patients. No significant perioperative complications occurred. Ten patients were alive and clinically stable at follow-up visits ranging from 14 to 55 months. Two patients died from systemic tumor dissemination during the follow-up period. The lateral extracavitary approach is useful when extensive or difficult spinal and paraspinal exposure is required. The surgical aspects of these neoplasms and the technique of lateral extracavitary approach are described in detail.

Retropleural approach to the thoracic and thoracolumbar spine.

Retropleural thoracotomy was used in 15 patients for the management of ventral thoracic and thoracolumbar spine abnormalities. This approach provides the shortest direct route to the anterior thoracic spine and avoids pleural cavity entry. A detailed description of retropleural thoracotomy and the clinical experiences of 15 patients treated with it are presented.

Anatomic principles of intradural spinal surgery.

In summary, the predominate role of surgery as the definitive treatment modality for the vast majority of intradural pathology provides a unique opportunity to improve outcome through continued advances in microsurgery. There is also, however, the added responsibility that comes with the treatment of benign and generally nonlife-threatening pathology, that is, an increasing expectation of cure and anticipation of preserved neurologic function. Successful intervention is maximized by the surgeon who recognizes that microsurgical technique and judgment are learned skills obtained only through experience but developed within a framework of anatomic principles and an understanding of how anatomy is altered by specific pathologic processes.

Monitoring of intraoperative motor-evoked potentials under conditions of controlled neuromuscular blockade.

Motor-evoked potentials were recorded after electrical spinal cord stimulation in 19 patients undergoing neurosurgical or orthopedic procedures. Anesthesia was maintained with nitrous oxide, opioids, and inhaled anesthetics. Vecuronium was infused sufficient to eliminate 90% of twitch tension. The spinal cord was stimulated using either epidural or subarachnoid electrodes. Compound muscle action potentials were recorded from quadriceps and tibialis anterior muscles. Well-formed, stable motor-evoked potentials were recorded in all but one patient, in whom a preexisting myelopathy was felt to preclude recording. Intraoperative deterioration of motor-evoked potentials occurred in one patient who had a postoperative neurologic deficit. This study demonstrates the feasibility and utility of intraoperative motor tract monitoring using direct spinal cord stimulation. Controlled neuromuscular blockade permits recording of compound muscle action potentials while eliminating patient motor activity that could interfere with surgery.