Clark Watts

Persistent Back Pain and Sciatica in the United States: Patient Characteristics

Low back pain is an extremely common, seriously disabling, nonfatal public health problem worldwide. The National Low Back Pain Study was a multicenter study of a large, heterogeneous group of patients who have been referred to either a neurosurgeon or an orthopedic surgeon for the evaluation and treatment of a persistent complaint of low back pain. In this paper, we characterize persistent low back pain patients and their complaints, describe the impact of persistent low back pain on the patients functional and psychological status, report on the patients medical characteristics, and identify treatments that are currently prescribed for these patients. Persistent low back pain is most common among people in their mid-to-late thirties and early-to-mid forties. The patients are mostly white, well educated, and generally affluent. The majority are gainfully employed, but some quit working because of pain and those who do tend to be less educated, and more likely to be involved in litigation. The average patient has had low back pain intermittently for 10 years. The pain is usually well localized but its severity varies considerably. Besides pain, most persistent low back pain patients report a variety of motor and sensory deficits. Patients also report significant functional impairment at work, at play, and at home. The typical patient does not, however, display significant psychological distress. Most patients have consulted multiple health care providers, have received a variety of treatments, and have used a variety of medications to alleviate pain; a few have been subjected to more aggressive treatment measures including surgery, intradiscal therapy, and narcotic and psychoactive drugs. None of these treatments has been effective. Physical examinations of these patients do not provide significant clues for making a definitive diagnosis. Nonspecific abnormalities such as muscle spasm, tenderness, and trigger points are quite common, but motor weakness and sensory deficits in the lower extremities, and reflex changes in the knees and ankles, are much less common. The classic combination of reflex changes, motor weakness, and sensory deficits associated with specific protruded discs are extremely rare even though one of three patients had a diagnosis of disc herniation. Diagnostic imaging studies revealed that the majority of persistent low back pain patients have spondylotic abnormalities involving root compression or lumbar instability or both, with root compression as the primary cause of the complaint. Myofascial syndrome and lumbar instability were the next most common diagnoses. After a thorough evaluation by specialists in spinal disorders, three of five persistent low back pain patients were prescribed an additional course of conservative therapy, one of five was prescribed surgery, and the rest were prescribed no treatment. Persistent low back pain patients appear to be a distinct group of low back pain patients who are different from patients who have similar nonpersistent acute symptoms and those who have the chronic pain syndrome characterized by significant behavioral and psychological co-morbidities.

Osmotic blood-brain barrier disruption and chemotherapy in the treatment of high grade malignant glioma: patient series and literature review

SummaryIn the past, chemotherapeutic treatment of patients with high grade malignant gliomas following surgery and radiation has not added significantly to the 12–14 month median survival rate. Over four years, 37 patients with high grade malignant gliomas underwent 246 treatment procedures with a combination of methotrexate, cyclophosphamide, and procarbazine given in association with hyperosmolar mannitol-induced transient breakdown of the blood-brain barrier. These patients have demonstrated a median survivorship of 22 months after considering age, Karnofsky Performance Score, and necrosis by the Cox Proportional Hazards model. The study group had a mean age of 43 years, and mean Karnofsky Performance Score of 67%. Sixty-five percent of the procedures had well-documented barrier disruption. Sixteen percent remained in complete remission while 24 patients (65%) had partial or temporary remission. Progression-free intervals after blood-brain barrier disruption/chemotherapy ranged from 1–47 (mean 15) months. Neurotoxicity has been minimal with one peri-procedural mortality and five patients suffering an increase in neurologic deficit after a procedure. The results of this study are consistent with and further extend the reported literature on this method of brain tumor therapy as described in other centers. Chemotherapy in conjunction with osmotic disruption of the blood-brain barrier may provide the pharmacokinetic advantage sufficient to significantly improve survival in patients with high grade malignant glioma.

Three-dimensional computer reconstructions of brain lesions from surface contours provided by computed tomography: a prospectus

We present a prospectus on the use of computer graphics for the three-dimensional reconstruction and visualization of brain lesions from computed tomographic head examinations, including an algorithm that utilizes surface contour information to reconstruct and display three-dimensional anatomical sites. We provide examples of the use of this algorithm. We offer an algorithm for estimation of the volume and surface area of anatomical sites. The advantages and disadvantages for the clinical use of these algorithms are discussed.

Utilization of somatosensory evoked cortical potentials in spinal cord injury. Prognostic limitations.

The prognostic value of somatosensory evoked cortical potentials (SECP) for clinical recovery was studied in 71 patients with complete (28) and incomplete (43) spinal injuries. While the absence of an SECP was associated with no clinical recovery, the presence of an SECP was of little value in predicting the clinical state at the time of examination or the potential for recovery

Spinal cord glioma following irradiation for Hodgkin's disease

A 21‐year‐old patient, after radiation therapy to the mediastinum for Hodgkins disease, died six years later of a spinal cord glioma, believed to be caused by irradiation therapy. That the x‐ray therapy provoked neoplastic changes seems likely, although it could be coincidental.

Meningioma following irradiation

The case of a young woman who developed initial symptoms of an intracranial mass lesion 17 years after undergoing irradiation for a port‐wine stain of the right fronto‐temporal and periorbital scalp and face is reported. A right sphenoid wing meningioma was removed 6 years later. The possible relationship between the development of the meningioma and the previous radiotherapy is discussed.

Further Studies with a Noninvasive Method of Intracranial Pressure Estimation

A linear relationship between elevated intracranial pressure in patients with hydrocephalus and with cerebral edema and a latency shift of the N2 wave of the flash-evoked cortical potential is demonstrated. Although the relationship is good at pressures of 200 to 300 mm H2O, it is excellent at pressures above 300 mm H2O. This relationship establishes a reliable noninvasive method of estimating intracranial pressure.

Comparison of laser and radiofrequency dorsal root entry zone lesions in cats

Dorsal root entry zone lesions are effective in the control of intractable pain in several types of spinal cord injuries. Traditionally, these lesions have been made with the radiofrequency technique. This is effective, but has the drawback of being laborious, and there is a significant incidence of permanent weakness. We have evaluated the carbon dioxide laser, hoping that it would be both faster and more controlled, thereby offering the chance to lower the complication rate. In comparing a parallel series of radiofrequency and laser dorsal root entry zone lesions along the cats spinal cord, we observed that the radiofrequency lesion was larger. In addition, it had 3 times more variability in its size than the laser lesion. We attribute this in part to the nature of the laser in making a very precise and reproducible lesion. Second, the extremely brief pulse of the laser, a fraction of a second, means that movement of the spinal cord from respiration and heartbeat and movement of the surgical instrument from the surgeons hand become far less important in inducing lesion variability. We also studied for 2 months a series of chronic cats; there were no complications due to the laser. This work suggests that the laser is a useful instrument for dorsal root entry zone lesions, but requires more precise aiming and focusing.

A preliminary study of a traumatic injury prevention program

Abstract This study examined the long-term impact of a five component spinal cord injury prevention program presented to adolescents. A sample of 445 teenagers who attended a junior high school in which an educational intervention was presented three years earlier and a control group of 379 students who had not been exposed to the intervention completed a questionnaire assessing their safety knowledge, attitudes, and self-reported behaviors. Total scores on the questionnaire between treatment and control groups differed significantly. Students in the treatment group reported significantly more frequent seat belt use, stronger belief that seat belts were important to their safety, lower likelihood of riding with friends who had been drinking, higher rates of friends use of seat belts, greater awareness of the age group most likely to be injured, and increased knowledge that they could prevent spinal cord injury.

Testing the Hydrocephalus Shunt Valve

Unwanted results of shunting for hydrocephalus include slit and asymmetrical ventricles and the conversion of communicating hydrocephalus to noncommunicating hydrocephalus. Evidence suggests this may be due to a mismatch between the pressure/flow performance characteristics of the shunt valve and the pathologic hydrodynamics of the ventricular cerebrospinal fluid. Commercially available shunts are currently tested using a steady-state pressure/flow method. We have utilized a bench testing method which incorporates pulsed flow and varying compliance. Results indicate that with minimal compliance in the system, opening and closing pressures differ markedly in value with pulsed flow as compared to steady-state testing. The greater the compliance the less deviation was noted. It is recommended more effort be made to understand the value of matching pressure/flow characteristics of valve to the individual hydrocephalic state.