Herniated lumbar disc disease in patients with malignancy.

Six patients with cancer presented with signs and symptoms of a lumbar herniated disc syndrome due to a herniated lumbar disc. The differential diagnosis and literature are reviewed. In four of the six, the patients' complaints were attributed to the malignancy, with delay in diagnosis and institution of appropriate therapy. In two of the patients, treatment was administered for presumed spinal metastasis with radiation therapy and/or chemotherapy with castration before the correct diagnosis was made. Surgery was performed on all six patients confirming the diagnosis of a herniated lumbar disc at the involved level and relieving the patients' pain.

Translabyrinthine removal of cerebellopontine angle meningiomas.

The authors report two cases of the microscopic total removal of meningiomas in the region of the cerebellopontine angle using the translabyrinthine approach. Although both tumors were larger than 4 cm, the only resulting neurological deficit was ipsilateral hearing loss. The translabyrinthine approach may be an alternative measure in dealing with these difficult lesions.

Evaluation and surgical management of peripheral nerve problems.

OBJECTIVE: To illustrate how an understanding of the basic biological responses of peripheral nerves to injury is important in formulating a rational treatment plan. METHODS: Peripheral nerve anatomy and physiology are described in a context that is relevant to understanding the different grades of peripheral nerve injury. Methods of evaluating and treating peripheral nerve injuries both medically and surgically are reviewed. Relevant scientific studies with potential clinical impact are also discussed. RESULTS: The clinical symptoms, physical findings, and electrodiagnostic and imaging test results relevant to the diagnosis of peripheral nerve problems are reviewed. Conventional and new medical or surgical strategies in the management of peripheral nerve injuries and mass lesions are described. CONCLUSION: The diagnosis and treatment of peripheral nerve injuries follow logically from an understanding of the biological responses of peripheral nerves after injury and during recovery.

Ulnar nerve entrapment at the elbow: correlation of magnetic resonance imaging, clinical, electrodiagnostic, and intraoperative findings.

The diagnosis of ulnar nerve entrapment at the elbow has relied primarily on clinical and electrodiagnostic findings. Recently, magnetic resonance imaging (MRI) has been used in the evaluation of peripheral nerve entrapment disorders to document signal and configuration changes in nerves. We performed a prospective study on a population of 31 elbows in 27 patients with ulnar nerve entrapment at the elbow. The study correlated MRI findings with clinical, electrodiagnostic, and operative findings. A control population consisting of 10 asymptomatic subjects also was studied by MRI. Electrodiagnostic evaluation confirmed ulnar neuropathy in 24 (77%) elbows of the 31, with localization to the elbow region in 21 (68%). MRI, using a short tau inversion recovery sequence, demonstrated increased signal of the ulnar nerve in 30 (97%) elbows of the 31 and enlargement of the ulnar nerve in 23 (74%). No MRI abnormalities were found in the control population. MRI signal increase of the ulnar nerve occurred an average of 27 mm proximal to the distal humerus and extended distally an average of 4 mm below the distal humerus. The mean total length of increased ulnar nerve signal was 34 mm. Ulnar nerve enlargement occurred an average of 19 mm proximal to the distal humerus and extended distally an average of 8 mm above the distal humerus. The mean total length of ulnar nerve enlargement was 12 mm. The 12 patients who underwent a surgical procedure for ulnar nerve entrapment were found to have ulnar nerve compression, with 9 (75%) having excellent and 3 (25%) having good postoperative results. In this study, MRI was both sensitive and specific in diagnosing ulnar nerve entrapment at the elbow as defined by clinical, electrodiagnostic, and operative findings.

Carpal tunnel syndrome: correlation of magnetic resonance imaging, clinical, electrodiagnostic, and intraoperative findings.

We undertook a prospective study of 43 wrists in 32 patients who had been clinically diagnosed as having carpal tunnel syndrome (study group) and 5 wrists in people who had no symptoms (control group), correlating the clinical, electrodiagnostic, intraoperative, and magnetic resonance imaging (MRI) findings. MRI of the carpal tunnel and thenar eminence was performed, using coronal and axial T1- and T2-weighted, proton density, and short tau inversion recovery sequences. Abnormalities of the median nerve, as revealed by MRI, were found in 43 of 43 (100%) wrists in the study group and in 0 of 5 (0%) wrists in the control group. Increased signal of the median nerve was seen in 41 of 43 (95%) wrists, increased signal of the flexor tendon sheath in 41 of 43 (95%), volar bowing of the flexor retinaculum in 39 of 43 (91%), increased distance between the flexor tendons in 37 of 43 (86%), and abnormal nerve configuration in 28 of 43 (65%). Increased short tau inversion recovery signal of the thenar muscles was found in 5 of 43 (12%) wrists, all of which had undergone severe denervation changes, as revealed by electromyography. Operative release was performed for 27 of 43 (63%) wrists, and follow-up was obtained for 42 of 43 (98%). A good or excellent postoperative outcome resulted for 20 of 27 (74%) patients, a fair outcome for 2 of 27 (7%), and a poor outcome for 4 of 27 (15%), and 1 of 27 (4%) patients was lost to follow-up. For patients undergoing carpal tunnel release whose MRI revealed an abnormal nerve configuration, the outcome was improved, with good or excellent results in 15 of 18 (83%) patients. No association with outcome was seen with median nerve or flexor tendon signal changes, increased interspace between the flexor tendons, or flexor retinaculum bowing. Our results indicate that MRI is a sensitive diagnostic modality that can demonstrate signal and configurational abnormalities of the median nerve in patients diagnosed with carpal tunnel syndrome. Increased signal of the thenar muscles, as revealed by MRI, using short tau inversion recovery sequences, occurs only in muscles that have undergone severe denervation changes, as revealed by electromyography.

Magnetic resonance imaging signal changes in denervated muscles after peripheral nerve injury.

The evaluation of peripheral nerve disorders has traditionally relied on a clinical history, physical examination, and electrodiagnostic studies. Recent studies have used magnetic resonance imaging (MRI) to evaluate a variety of both nerve and muscle disorders. In this article, we describe the use of MRI, using short-tau inversion recovery (STIR) sequences, to evaluate muscle signal characteristics in a variety of peripheral nerve disorders. A total of 32 patients were studied, and 12 representative cases are discussed in detail. Increased STIR signal in muscle was seen in cases of severe axonotmetic injuries involving the transection of axons producing severe denervation changes on electromyography. The increased STIR signal in denervated muscles was seen as early as 4 days after the onset of clinical symptoms, which is significantly earlier than changes detected on electromyography. The MRI signal changes were reversible when the recovery of motor function occurred as a result of further muscle innervation. In cases of neurapraxic nerve injuries, characterized by conduction block without axonal loss, the STIR signal in muscle was normal. These findings show that MRI using STIR sequences provides a panoramic visual representation of denervated muscles useful in localizing and grading the severity of peripheral nerve injury secondary to either disease or trauma. MRI using STIR sequences may therefore play an important role in the prediction of clinical outcome and the formulation of appropriate therapy early after peripheral nerve injury.

Magnetic resonance neurography for cervical radiculopathy: a preliminary report.

Magnetic resonance neurography was used to directly image cervical spinal nerves in patients with clinical and radiographic evidence of cervical radiculopathy. A magnetic resonance imaging phased-array coil system was used to obtain high-resolution coronal T1-weighted spin echo, coronal/axial T2-weighted fast spin echo with fat saturation, and coronal/axial fast short tau inversion recovery weighted images of the cervical spine and spinal nerves. Three patients with neck and upper extremity pain and one asymptomatic volunteer were studied. The T2-weighted and the fast short tau inversion recovery images demonstrated markedly increased signal in the proximal portion of the affected spinal nerves. In two patients, contrast-to-noise measurements of the affected spinal nerves showed a markedly increased intensity compared with that of the noninvolved spinal nerves. Our findings demonstrate that phased-array coils used in conjunction with magnetic resonance neurography sequences can detect signal abnormalities within compressed cervical spinal nerves in patients with corresponding radicular symptoms and findings. This technique may prove to be helpful in evaluating patients with multilevel disc and/or spondylotic disease of the cervical spine.

Magnetic resonance neurography of peripheral nerve lesions in the lower extremity.

OBJECTIVE: We describe the clinical application and utility of high-resolution magnetic resonance neurography (MRN) techniques to image the normal fascicular structure of peripheral nerves and its distortion by mass lesions or trauma in the lower extremity. METHODS: MRN images were obtained using a standard 1.5 Tesla magnet and custom built phased-array coils. Patients were imaged using T1-weighted spin echo without and with gadolinium, T2-weighted fast spin echo with fat peripheral nerve tumors (three neurofibromas and one schwannoma), two with intraneural cysts, and three with traumatic peripheral nerve lesions. Six patients with peripheral nerve mass lesions underwent surgery, thereby allowing MRN images to be correlated with intraoperative and pathological findings. RESULTS: Preoperative MRN accurately imaged the normal fascicular anatomy of peripheral nerves and precisely depicted its relation to tumor and cystic lesions. Increased signal on T2-weighted fast spin-echo and short tau inversion recovery fast spin-echo pulse sequences was seen in the peripheral nerve fascicles of patients with clinical and electrodiagnostic evidence of nerve injury. CONCLUSION: MRN proved useful in the preoperative evaluation and planning of surgery in patients with peripheral nerve lesions.

Sequential angiographic studies demonstrating delayed development of an acute epidural hematoma. Case report.

A case is presented in which the delayed development of an acute epidural hematoma within 12 hours of a head injury was documented by serial cerebral angiography. A possible mechanism for the delayed evolution of the epidural hematoma is discussed.

Arteriovenous malformation and glioma: coexistent or sequential? Case report.

A 9-year-old girl was evaluated for behavioral changes and seizures. Initial computerized tomography and cerebral angiography revealed a left cerebral vascular mass, diagnosed as an arteriovenous malformation. An embolization procedure was attempted but was terminated before completion because the patient developed a right hemiparesis. Her right-sided neurological deficit subsequently increased with enlargement of the mass lesion. On follow-up cerebral angiography approximately 2 years later the vascular malformation was no longer demonstrated. Biopsy of the mass lesion revealed it to be an anaplastic astrocytoma. This case is reported with a review of the literature on the coexistence of a brain tumor and a vascular malformation, the difficulties in diagnosis, and possible etiologies.

Intraoperative ultrasound for monitoring anterior cervical vertebrectomy. Technical note.

The authors describe the use of intraoperative ultrasonography with a small high-frequency (15 mHz) probe for evaluation of the extent of lateral bone removal during anterior cervical vertebrectomy. The relationship of the bone resection margins to the lateral aspect of the spinal cord was visualized. Postoperative computerized tomography scans revealed the extent of bone removal to be similar to that demonstrated by ultrasound. Intraoperative ultrasonography may be useful during anterior cervical surgery to assure adequate decompression of the spinal canal and spinal cord.

Resolution of petrous internal carotid artery stenosis after transluminal angioplasty. Case report.

Percutaneous transluminal angioplasty is commonly used for treatment of peripheral vascular disease, but only recently has it been applied to craniocervical lesions. The successful use of percutaneous transluminal angioplasty for treatment of an isolated high-grade stenosis of the petrous internal carotid artery is described in a patient with progressive ischemic symptoms despite maximum medical management. At his 2-year follow-up examination, the patient remained asymptomatic with angiographic evidence of progressive resolution of the stenotic lesion and indirect evidence of improved hemispheric blood flow ipsilateral to the lesion. Percutaneous transluminal angioplasty may provide an effective means of treatment for selective intracranial artherosclerotic stenosis.

Application of magnetic resonance neurography in the evaluation of patients with peripheral nerve pathology.

Currently, diagnosis and management of disorders involving nerves are generally undertaken without images of the nerves themselves. The authors evaluated whether direct nerve images obtained using the new technique of magnetic resonance (MR) neurography could be used to make clinically important diagnostic distinctions that cannot be readily accomplished using existing methods. The authors obtained T2-weighted fast spin-echo fat-suppressed (chemical shift selection or inversion recovery) and T1-weighted images with planes parallel or transverse to the long axis of nerves using standard or phased-array coils in healthy volunteers and referred patients in 242 sessions. Longitudinal and cross-sectional fascicular images readily distinguished perineural from intraneural masses, thus predicting both resectability and requirement for intraoperative electrophysiological monitoring. Fascicle pattern and longitudinal anatomy firmly identified nerves and thus improved the safety of image-guided procedures. In severe trauma, MR neurography identified nerve discontinuity at the fascicular level preoperatively, thus verifying the need for surgical repair. Direct images readily demonstrated increased diameter in injured nerves and showed the linear extent and time course of image hyperintensity associated with nerve injury. These findings confirm and precisely localize focal nerve compressions, thus avoiding some exploratory surgery and allowing for smaller targeted exposures when surgery is indicated. Direct nerve imaging can demonstrate nerve continuity, distinguish intraneural from perineural masses, and localize nerve compressions prior to surgical exploration. Magnetic resonance neurography can add clinically useful diagnostic information in many situations in which physical examinations, electrodiagnostic tests, and existing image techniques are inconclusive.

Treatment of recurrent peripheral nerve entrapment problems: role of scar formation and its possible treatment.

Surgical management of peripheral nerve entrapment syndromes is usually successful, but the recurrence of symptoms after initial improvement can and does occur. Extraneural fibrosis is one possible cause of recurrent peripheral nerve problems as a result of nerve compression or tethering. Several approaches to prevent extraneural scarring after surgery have been studied, including wrapping the involved nerve with a graft, the application of various chemical compounds, and radiation. ADCON-T/N, an antiscar bioabsorbable gel device was evaluated in a retrospective clinical review. Sixty-seven percent of patients treated with ADCON-T/N after reoperation of a peripheral nerve experienced prolonged clinical improvement compared with 50% of patients who did not receive ADCON-T/N. These preliminary results suggest that ADCON-T/N may prove to be clinically useful in the surgical treatment of peripheral nerve problems. Additional more rigorous clinical studies are necessary, however.

Vascular and visceral injuries associated with lumbar disc surgery: medicolegal implications.

Symptomatic perforation of the anterior annulus fibrosus/anterior longitudinal ligament during surgery for herniated lumbar disc disease is one of the more solemn and sobering complications experienced by neurosurgeons or orthopedic surgeons. This complication frequently results in the death of the patient. Its occurrence is probably more common than the medical community would expect. The authors report 21 cases since 1985 in which an injury to an intra-abdominal vessel or viscera occurred. In all cases litigation resulted and a settlement or verdict was rendered. A review of the literature is presented and the medicolegal implications of symptomatic ventral perforations of the annulus fibrosus/anterior longitudinal ligament are discussed.

Unintended "incidental" durotomy during surgery of the lumbar spine: medicolegal implications.

A review of 146 medical malpractice cases involving surgery of the lumbar spine disclosed that unintended "incidental" durotomy (23 cases) was the second most frequently named occurrence. In each instance there was an associated alleged complication or sequelae. There appears to be a subset of patients in whom an unintended "incidental" durotomy is associated with perioperative morbidity and long-term sequelae. Considering the frequency with which a dural tear is listed as one of the complaints in medical malpractice cases involving surgery of the lumbar spine, it cannot be considered an entirely "benign event."

Intraoperative ultrasonic microbubble contrast in determining the patency of the foramen of Monro.

A case is reported in which intraoperative ultrasonic microbubble contrast was used to demonstrate the patency of the foramen of Monro following resection of a colloid cyst.

Persistent feeding arteries to angiographically completely embolized arteriovenous malformation demonstrated by intraoperative color-flow Doppler testing: report of two cases.

Two cases of arteriovenous malformation (AVM) treated preoperatively by endovascular embolization that appeared to be completely occluded after embolization are presented. Seven and 12 days later, respectively, these patients underwent resection of their AVM. At the time of surgery, intraoperative color-flow Doppler studies revealed persistent feeding arteries to an active residual nidus of the AVM. The significance of this finding is presented in light of previous published literature.

Sciatic nerve injury in a patient undergoing laparoscopy.

A case of injury to the sciatic nerve at the time of laparoscopy is presented. The problem can generally be prevented, and the resolution, although lengthy, ususally is complete.