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Jason A. Heth, Matthew A. Howard III, and Nicholas Rossi

✓ The authors report on a patient who developed acute-onset paraparesis after underoing a thoracotomy 40 years earlier for a carcinoid adenoma. No infectious or neoplastic origin could be found to explain the patient's current clinical course and radiographic findings. The postoperative events in this case are discussed, as well as the literature regarding postthoracotomy complications.

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Timothy W. Vogel, Brian J. Dlouhy, and Matthew A. Howard III

Object

The object of this study was to evaluate the causes of plunging events associated with automatic-releasing cranial perforators at the authors' institution.

Methods

The authors analyzed a consecutive series of 1652 cranial procedures involving one type of automaticreleasing cranial perforator over a 2-year period. Plunging occurrences were recorded for 2 drill speeds: 1000 rpm in the 1st year and 800 rpm during the 2nd year. Intraoperative observations, neuroimaging studies, and clinical data were evaluated for each plunging event.

Results

The authors identified 9 plunging events for an overall incidence of 0.54%. In the 1st year, they identified 2 plunging events at a speed of 1000 rpm for an incidence of 0.19%. In an effort to reduce this occurrence, the speed of the drill was lowered to 800 rpm. There were 7 additional events, for a significantly increased incidence of 1.16% (p = 0.014, Fisher exact test) after the change was implemented. These cases spanned a number of procedures in adults and pediatric patients, including ventriculostomy placement, craniotomies for tumor resection, tumor biopsy, and endoscopic third ventriculostomy. Despite plunging, no immediate postoperative complications were noted on clinical examination.

Conclusions

While technology continues to improve cranial perforator performance, the use of such a device is still associated with a risk of complications causing dural lacerations and injury to the underlying cortex. Decreasing the drill speed may not decrease the incidence of plunging.

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Taylor J. Abel, Timothy Walch, and Matthew A. Howard III

Advances in functional neurosurgery, including neuromodulation and more recently ultrasonic ablation of basal ganglia structures, have improved the quality of life for patients with debilitating movement disorders. What is little known, however, is that both of these neurosurgical advances, which remain on the cutting edge, have their origin in the pioneering work of Russell Meyers, whose contributions are documented in this paper. Meyers' published work and professional correspondence are reviewed, in addition to documents held by the Department of Neurosurgery at the University of Iowa. Meyers was born in Brooklyn, New York, and received his neurosurgical training at hospitals in New York City under Jefferson Browder. In 1939, a chance encounter with a young woman with damaged bilateral ventral striata convinced Meyers that the caudate could be resected to treat Parkinsonism without disrupting consciousness. Shortly thereafter, he performed the first caudate resection for postencephalitic Parkinsonism. In 1946, Meyers became the first chairman of neurosurgery at the State University of Iowa (now the University of Iowa), which led to the recruitment of 8 faculty members and the training of 18 residents during his tenure (1946–1963). Through collaboration with the Fry brothers at the University of Illinois, Meyers performed the first stereotactic ultrasonic ablations of deep brain structures to treat tremor, choreoathetosis, dystonia, intractable pain, and hypothalamic hamartoma. Meyers left academic neurosurgery in 1963 for reasons that are unclear, but he continued clinical neurosurgery work for several more years. Despite his early departure from academic medicine, Meyers' contributions to functional neurosurgery provided a lasting legacy that has improved the lives of many patients with movement disorders.

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Timothy W. Vogel, Brian J. Dlouhy, and Matthew A. Howard III

Spontaneous intracranial hypotension (SIH) is a syndrome with serious neurological sequelae. As demonstrated by the following report, recurrent episodes of SIH can be difficult to diagnose when associated with other neurosurgical procedures, such as craniectomies. In this paper, the authors demonstrate SIH presenting as a subdural hematoma with recurrence of CSF leaks. Spontaneous intracranial hypotension was further complicated by paradoxical herniation following a craniectomy. Treatment of SIH necessitated multiple epidural blood patches for CSF leaks at different spinal levels and at different times. The efficacy of each epidural blood patch was confirmed with radionuclide imaging. Confirmation of effective blood patch placement may be useful for identifying patients at risk for a failed epidural blood patch or for patients whose neurological examination results have not fully improved.

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Matthew A. Howard III, Ralph G. Dacey Jr., and H. Richard Winn

✓ Animal models of Parkinson's disease and Alzheimer's disease have shown dramatic functional improvement after transplantation of embryonic neurons into denervated regions of the adult brain. Because of the ethical and logistic problems associated with the use of human embryonic brain tissue, cross-species transplants are an attractive alternative. An experimental model of cross-species brain transplantation was developed to evaluate cell survival in untreated and cyclosporin A (CyA)-treated animals. Cholinergic ventral neurons from embryonic mice were transplanted into the frontal lobes of 18 adult Sprague-Dawley rats using a cell suspension technique. Nine animals were treated for 13 days with CyA (10 mg/kg/day) and nine were not treated. Twelve weeks after transplantation, frozen sections through the transplant volume were obtained. Alternate sections were prepared with hematoxylin and eosin and acetylcholine esterase stains. Cell counts through a 2-cu mm volume incorporating the transplant were compared to a contralateral control volume. Eight of the nine untreated transplants were successful (mean transplant cells ± standard error of the mean: 90.7 ± 19.4/2 cu mm). All of the nine CyA-treated transplants survived, with mean transplant count 28.7 cells/2 cu mm greater than untreated transplants (mean increase 28.7: p ≤ 0.05, Wilcoxon matched-pairs signed ranks test). It is concluded that: 1) this model is useful for quantitating transplant cell survival; 2) untreated xenografts survive well; and 3) a 13-day course of CyA improved long-term graft survival.

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Kirsten E. Stoner, Kingsley O. Abode-Iyamah, Vincent A. Magnotta, Matthew A. Howard III, and Nicole M. Grosland

OBJECTIVE

Cervical myelopathy (CM) is a common and debilitating form of spinal cord injury caused by chronic compression; however, little is known about the in vivo mechanics of the healthy spinal cord during motion and how these mechanics are altered in CM. The authors sought to measure 3D in vivo spinal cord displacement and strain fields from MR images obtained during physiological motion of healthy individuals and cervical myelopathic patients.

METHODS

Nineteen study participants, 9 healthy controls and 10 CM patients, were enrolled in the study. All study participants had 3T MR images acquired of the cervical spine in neutral, flexed, and extended positions. Displacement and strain fields and corresponding principal strain were obtained from the MR images using image registration.

RESULTS

The healthy spinal cord displaces superiorly in flexion and inferiorly in extension. Principal strain is evenly distributed along the spinal cord. The CM spinal cord displaces less than the healthy cord and the magnitude of principal strain is higher, at the midcervical levels.

CONCLUSIONS

Increased spinal cord compression during cervical myelopathy limits motion of the spinal cord and increases spinal cord strain during physiological motion. Future studies are needed to investigate how treatment, such as surgical intervention, affects spinal cord mechanics.

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Ralph G. Dacey, Oliver E. Flouty, M. Sean Grady, Matthew A. Howard III, and Marc R. Mayberg

OBJECTIVE

When performing ventriculoperitoneal shunt surgery it is necessary to create a subgaleal pocket that is of sufficient size to accommodate a shunt valve. In most cases the valve is placed over the posterior skull where the galea begins to transition to suboccipital neck fascia. Dense fibrous attachments in this region of the skull make it technically awkward to develop the subgaleal valve pocket using standard scissors and a blunt dissection technique. In this report the authors describe a new device that enables surgeons to create the shunt valve pocket by using a simple semi-sharp dissection technique.

METHODS

The authors analyzed the deficiencies of the standard valve pocket dissection technique and designed shunt scissors that address the identified shortcomings. These new scissors allow the surgeon to sharply dissect the subgaleal space by using an efficient hand-closing maneuver.

RESULTS

Standard surgical scissors were modified to create shunt scissors that were tested on the benchtop and used in the operating room. In all cases the shunt scissors proved easy to use and allowed the efficient and reliable creation of a subgaleal valve pocket in a technically pleasing manner.

CONCLUSIONS

Shunt scissors represent an incremental technical advance in the field of neurosurgical shunt operations.

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Francis J. Jareczek, Marshall T. Holland, Matthew A. Howard III, Timothy Walch, and Taylor J. Abel

Neurosurgery for the treatment of psychological disorders has a checkered history in the United States. Prior to the advent of antipsychotic medications, individuals with severe mental illness were institutionalized and subjected to extreme therapies in an attempt to palliate their symptoms. Psychiatrist Walter Freeman first introduced psychosurgery, in the form of frontal lobotomy, as an intervention that could offer some hope to those patients in whom all other treatments had failed. Since that time, however, the use of psychosurgery in the United States has waxed and waned significantly, though literature describing its use is relatively sparse. In an effort to contribute to a better understanding of the evolution of psychosurgery, the authors describe the history of psychosurgery in the state of Iowa and particularly at the University of Iowa Department of Neurosurgery. An interesting aspect of psychosurgery at the University of Iowa is that these procedures have been nearly continuously active since Freeman introduced the lobotomy in the 1930s. Frontal lobotomies and transorbital leukotomies were performed by physicians in the state mental health institutions as well as by neurosurgeons at the University of Iowa Hospitals and Clinics (formerly known as the State University of Iowa Hospital). Though the early technique of frontal lobotomy quickly fell out of favor, the use of neurosurgery to treat select cases of intractable mental illness persisted as a collaborative treatment effort between psychiatrists and neurosurgeons at Iowa. Frontal lobotomies gave way to more targeted lesions such as anterior cingulotomies and to neuromodulation through deep brain stimulation. As knowledge of brain circuits and the pathophysiology underlying mental illness continues to grow, surgical intervention for psychiatric pathologies is likely to persist as a viable treatment option for select patients at the University of Iowa and in the larger medical community.

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Arnold H. Menezes, Scott C. Seaman, Matthew A. Howard III, Patrick W. Hitchon, and Elizabeth B. Takacs

OBJECTIVE

Tethered cord syndrome (TCS) has been well described in pediatric patients. Many recent reports of TCS in adult patients have grouped retethering patients with newly diagnosed ones without separately analyzing each entity and outcome. The authors reviewed their experience of newly diagnosed adult TCS patients to identify and explore TCS misdiagnosis, recognition, subtype pathology, and individual objective outcomes.

METHODS

This study included 24 adult patients (20 female and 4 male) who fit the criteria of being newly diagnosed and aged 20 years and older (age range 20–77 years). Preexisting dermal sinus was present in 6 patients, hypertrichosis in 5, skin tag/cleft/dimple and fatty subcutaneous masses in 5, scoliosis in 2, and neurological abnormalities in 4 patients. The pathology consisted of TCS with taut filum in 8 patients, conus lipoma with TCS in 7, diastematomyelia in 7, and cervical cord tethering in 2 patients. Of the 24 study patients, nondermatomal low-back or perineal pain occurred in 19 patients, bladder dysfunction in 21, and motor, sensory, and reflex abnormalities in 21 patients. Aggravating factors were repeated stretching, multiple pregnancies, heavy lifting, and repeated bending. Urological evaluation included bladder capacity, emptying, postvoid residuals, detrusor function, pelvic floor electromyography (EMG), bladder sensitivity, and sphincter EMG, which were repeated at 6 months and 1 year postoperatively. The follow-up was 1 to 30 years. Detailed postoperative neurological findings and separate patient outcome evaluations were recorded. Four of the 24 patients did not have an operation.

RESULTS

Resolution of pain occurred in 16 of the 19 patients reporting low-back or perineal pain. Motor and sensory complaints resolved in 17 of 20 patients. Regarding bladder dysfunction, in the 20 patients with available data, bladder function returned to normal in 12 patients, improved in 3 patients, and was unchanged in 5 patients. If the symptom duration was less than 6–8 months, there was recovery of all parameters of pain, bladder dysfunction, and neurological deficit, and recovery from hyperreflexia matched that from neurological deficit. Fifteen patients were employed preoperatively and returned to work, and an additional 3 others who were unable to work preoperatively were able to do so postoperatively.

CONCLUSIONS

Most adults with newly diagnosed TCS have unrecognized neurocutaneous abnormalities and neurological deficits. The triad of nondermatomal sacral or perineal pain, bladder dysfunction, and neurological deficit should not be confused with hip or degenerative lumbosacral disease. Addressing the primary pathology often leads to successful results.

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M. Sean Grady, Matthew A. Howard III, Ralph G. Dacey Jr., Walter Blume, Michael Lawson, Peter Werp, and Rogers C. Ritter

Object. The magnetic stereotaxis system (MSS) is a device designed to direct catheter tips through magnetic forces. In this study the authors tested the safety and performance of the MSS in directing catheters through a nonlinear path to obtain biopsy specimens in pig brains.

Methods. Sixteen pigs underwent biopsy of the frontal brain region with the aid of an MSS (11 pigs) or a standard stereotactic biopsy tool (five pigs). Surgical preparation consisted of placement of six fiducial markers in the skull and the creation of a burr hole for attachment of a cranial bolt and passage of the biopsy catheter. The pigs underwent magnetic resonance (MR) imaging of the head to define a biopsy target and to plan a nonlinear path. Guided by the MSS, which used nearly real-time fluoroscopic imaging fused to the preoperative MR image, the authors advanced a catheter to the biopsy target. A biopsy tool was passed through the catheter and a tissue sample was obtained. The animals were observed for 3 to 5 days postoperatively, when they were assessed for neurological abnormalities or other signs of morbidity. Actual catheter placement was within 1.5 mm of the planned path to the biopsy site, using a minimum path radius of 30 mm. The registration error associated with the use of the MSS x-ray fluoroscopy and MR imaging averaged 1.7 mm. Tissue disruption caused by the MSS was similar to that of standard stereotactic procedures.

Conclusions. The MSS affords accurate and safe guidance of brain catheters in animals. The application tested here, brain biopsy, is one of a number of potential catheter-guided procedures.