Biomedical subjects
P A Ball
Publications and source records attributed to P A Ball.
William Jason Mixter (1880-1958). Ushering in the "dynasty of the disc".
William Jason Mixter was born in 1880 and graduated from the Harvard Medical School class of 1906. Like his father, Mixter was a prominent surgeon at the Massachusetts General Hospital, and in 1911 the two shared the job of overseeing all neurosurgery at that institution. By the early 1930s, W. J. Mixter was considered to be one of the nation's leading experts in spinal surgery, and he went on to become the first chief of the neurosurgery department at Massachusetts General Hospital. He served in the U. S. Army in both world wars and was actively involved in his local church community in Boston for many years. In 1934, at the age of 54, Mixter and Joseph S. Barr published an article on the intervertebral disc lesion in the New England Journal of Medicine. That article fundamentally changed the popular understanding of sciatica at that time, and for this work Mixter is generally credited by his contemporaries as being the man who best clarified the relation between the intervertebral disc and sciatica. Mixter and Barr's landmark report helped to establish surgery's prominent role in the management of sciatica at the time. Over the next few decades, discectomy surgery increased in popularity tremendously, and some refer to that period as the "dynasty of the disc."
Sensitivity of prevertebral soft tissue measurement of C3 for detection of cervical spine fractures and dislocations.
A prevertebral soft tissue measurement exceeding 4 to 5 mm at C3 on a lateral spine radiograph is considered to be evidence of cervical spine injury. The objective of this study was to determine the sensitivity of the prevertebral soft tissue measurement at C3 in patients with proven cervical spine fractures or dislocations and to determine if this measurement correlates with the location or mechanism of injury. Consecutive patients 16 years of age or older who were admitted from July 1988 to June 1995 to a tertiary referral hospital with a discharge diagnosis of cervical spine fracture or dislocation were retrospectively studied. Patients were excluded if an interpretable lateral cervical radiograph taken within 24 hours of the injury was unavailable, medical records were unavailable or incomplete, the injury was caused by penetrating trauma or attempted hanging, or retropharyngeal air was present on the lateral radiograph. For each study patient, the earliest available lateral radiograph was obtained, and the prevertebral soft tissue measurement at the inferior aspect of C3 was recorded. All medical records and reports of imaging studies were reviewed. Two hundred thirty-two patients were identified and 21 were excluded, leaving 212 study patients. Injuries were classified as high (C1 to C2), low (C3 to C7), anterior, or posterior. For each patient the mechanism of injury was inferred from the fracture pattern according to established criteria. For all patients the sensitivity of a prevertebral soft tissue measurement at C3 of > 4 mm was 66% (95% confidence interval [CI] 59, 72). For C1 to C2 (n = 71) and C3 to C7 (n = 138) injuries, the sensitivities were 64% (95% CI 56, 78) and 64% (95% CI 56, 72), respectively. For anterior (n = 95) and posterior (n = 70) injuries the sensitivities were 64% (95% CI 54, 74) and 64% (95% CI 52, 75), respectively. There was no statistically significant difference in the prevertebral soft tissue measurement at C3 for high versus low injury, anterior versus posterior injury, or mechanism of injury. These results show that the prevertebral soft tissue measurement at C3 is an insensitive marker of cervical spine fracture or dislocation and does not correlate with the location or mechanism of injury.
Magnetic resonance imaging for the evaluation of patients with occult cervical spine injury.
Because it is often difficult to diagnose accurately the structurally intact cervical spine after acute trauma, a series of patients was evaluated with magnetic resonance (MR) imaging to assess its efficacy for the evaluation and clearance of the cervical spine in a trauma victim in the early posttrauma period. Ultralow-field MR imaging was used to evaluate 174 posttraumatic patients in whom physical findings indicated the potential for spine injury or minor radiographic findings indicated injury. This series includes only those patients who did not appear to harbor disruption of spinal integrity on the basis of a routine x-ray film. None had clinically obvious injury. Of the 174 patients, 62 (36%) had soft-tissue abnormalities identified by MR imaging, including disc interspace disruption in 27 patients (four with ventral and dorsal ligamentous injury, three with ventral ligamentous injury alone, 18 with dorsal ligamentous injury alone, and two without ventral or dorsal ligamentous injury). Isolated ligamentous injury was observed in 35 patients (eight with ventral and dorsal ligamentous injury, five with ventral ligamentous injury alone, and 22 with dorsal ligamentous injury alone). One patient underwent a surgical fusion procedure, 35 patients (including the one treated surgically) were placed in a cervical collar for at least 1 month, and 27 patients were placed in a thermoplastic Minerva jacket for at least 2 months. All had a satisfactory outcome without evidence of instability. The T2-weighted sagittal images were most useful in defining acute soft-tissue injury; axial images were of minimal assistance. Posttraumatic soft-tissue cervical spine injuries and disc herniations (most likely proexisting the trauma) are more common than expected. A negative MR image should be considered as confirmation of a negative or "cleared" subaxial cervical spine. Diagnostic and patient management algorithms may be appropriately tailored by this information. Thus, MR imaging is useful for early acute posttrauma assessment in a very select group of patients.
Characteristics of cerebral gunshot injuries in the rural setting.
The rural CGW population has not yet undergone the metamorphosis experienced by its urban counterparts. Reminiscent of a past era, suicides far outweight homicides. Although many rural firearm injuries involve hunting accidents, these comprise only a small fraction of CGW at best. Similarly, although many rural firearm injuries involve shotguns or rifles, few CGW result from these weapons. Although the number of patients is small, those with shotgun or rifle injuries manifest lower mortality rates. The authors have confirmed the notion that caliber of civilian weapons is difficult to correlate with outcome. The geographic size of the rural catchment area is an important consideration because it must select a population able to withstand transfer. The authors noted an inverse relationship between length of time before arrival at the facility and mortality. The selection phenomenon probably accounts for the reduced mortality found in the authors series versus most others. Prognostic features of individual gunshot wounds are likely to be similar among varied populations when circumstances of the injury are matched. Thus, one expects similar features on initial examination and CT scan to have similar predictive value. The authors confirmed that CGS and specific deficits were strong predictors of outcome. No patient with a GCS score of 5 or less on admission survived. Absent pupillary response, absent brain stem function, presence of respiratory drive or cough only, and posturing were strong indicators of impending death. The authors confirmed the prognostic value associated with CT evidence of intraventricular hemorrhage, transventricular trajectory, transtentorial herniation, massive edema, and bihemispheric injury. Interestingly, presence of extensive facial fractures, an indicator of trajectory, suggested better outcome. Subarachnoid hemorrhage did not reach prognostic significance. Roughly half of the authors' patients had positive serum ethanol levels, although the test was unable to discern prognosis. Abnormality of any coagulation parameter and frank disseminated intravascular coagulation were correlated with poor outcome. Likewise, thrombocytopenia occurring within the first 24 hours was an indicator of poor prognosis. Although prophylactic antibiotics were not used in all cases, the authors encountered no deep or superficial infections in surviving patients. The prevalence of seizures in the authors' series despite prophylactic AED is unusually high. This feature merits further study.
A simple method to ensure proper screw position and plate size selection using the Morscher cervical spine locking plate. Technical note.
The use of bone plate instrumentation with screw fixation has proved to be a useful adjunctive measure in anterior cervical spine fusion surgery. Proper fitting, positioning, and attachment of this instrumentation have been shown to be frequently suboptimal if done without radiographic guidance. The most commonly used method of radiographic assistance for placement of this instrumentation is fluoroscopy. While this gives satisfactory technical results, it is expensive and time-consuming, and exposes the patient and the operating room personnel to ionizing radiation. The authors present a simple technique to ensure screw placement and plate fitting using Kirschner wires and a single lateral radiograph. This technique saves time, reduces exposure to radiation, and has led to satisfactory results in over 20 operative cases.
Fractures of the C-2 vertebral body.
Vertical C-2 body fractures are presented in 15 patients with clinical and imaging correlations that suggest the existence of a variety of mechanisms of injury. In these patients, clinical and imaging correlations were derived by: 1) defining the point of impact by clinical examination; 2) defining the point of impact by soft-tissue changes on cranial magnetic resonance (MR) imaging or computerized tomography (CT); 3) obtaining an accurate history of the mechanism of injury; and 4) spine imaging (x-ray studies, CT, and MR imaging) of the C-2 body fracture and surrounding bone and soft tissue. The cases presented involve the region located between the dens and the pars interarticularis of the axis. Although these fractures are rarely reported, they are not uncommon. An elucidation of their pathological anatomy helps to further the understanding of the mechanistic etiology of upper cervical spine trauma. A spectrum of mechanisms of injury causing upper cervical spine fractures was observed. The type of injury incurred is determined predominantly by the force vector applied during impact and the intrinsic strength and anatomy of C-2 and its surrounding spinal elements. From this clinical experience, two types of vertical C-2 body fractures are defined and presented: coronally oriented (Type 1) and sagittally oriented (Type 2). A third type of C-2 body fracture, the horizontal rostral C-2 fracture (Type 3), is added for completeness; this Type 3 fracture is the previously described Type III odontoid process fracture described by Anderson and D'Alonzo.
The sequential hook insertion technique for universal spine instrumentation application. Technical note.
A new technique of universal spine instrumentation insertion for the management of thoracic and lumbar spine instability is presented and the results in 10 patients are described. The technique involves the sequential insertion of Texas Scottish Rite Hospital (TSRH) central-post hooks, followed by hook fixation to the rod; force is then applied with correction of deformity, if needed. This allows for methodical, safe, and rapid instrumentation insertion. The new TSRH central-post hook configuration permits manipulation of the hook/rod relationships to the advantage of the surgeon (and patient) by providing more room for both hook insertion and hook/rod fixation. This technique has reduced operative time, facilitated ease of deformity correction, and provided uniformly acceptable early postsurgical results.
Intracerebral polyposis or osteoma?
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Hazards of parenteral treatment: do particles count?
After prolonged parenteral nutrition a 12 month old infant died with pulmonary hypertension and granulomatous pulmonary arteritis. A review of necropsy findings in 41 infants who had been fed parenterally showed that two of these also had pulmonary artery granulomata, while none of 32 control patients who died from sudden infant death syndrome had similar findings. Particulate contaminants have been implicated in the pathogenesis of such lesions and these were quantified in amino acid/dextrose solutions and fat emulsions using automated particle counting and optical microscope counting respectively. Parenteral feed infusions compounded for a 3000 g infant according to standard nutritional regimens were found to include approximately 37,000 particles between 2 and 100 microns in size in one day's feed, of which 80% were derived from the fat emulsion. In-line end filtration of intravenous infusions may reduce the risk of particle associated complications. A suitable particle filter is required for use with lipid.
Stereotactic biopsy in AIDS patients.
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Intracranial pressure with head elevation.
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Benign nasal polyposis presenting as an intracranial mass: case report.
An interesting case of benign nasal polyposis with intracranial extension and subsequent abscess formation is described. Its diagnosis and treatment are presented and the pathology is demonstrated. The literature related to this rare disease process is discussed in detail.
Egg and breast milk based nitrogen sources compared.
A nitrogen source based on egg protein (Vamin 9 glucose) and an alternative with an amino acid profile more similar to breast milk (Vaminolact), were compared in 14 parenterally fed infants. Subjects were randomly allocated to receive one or other amino acid solution, but were otherwise given identical diets. At the start of the study the two groups did not differ significantly in postconceptual age, postnatal age, or weight. Over a six day study period on a stable intake of intravenous nutrients there was no significant difference in growth or nitrogen retention between the two groups. Plasma amino acid profiles in those receiving Vamin 9 glucose, however, were frequently abnormal. Notably, mean concentrations of potentially neurotoxic phenylalanine and tyrosine were significantly higher (140% and 420%, respectively) in patients fed Vamin 9 compared with those given Vaminolact. An amino acid solution based on the composition of breast milk protein therefore brings plasma amino acid profiles during parenteral nutrition closer to those found in breast fed infants, and reduces in particular, the risks of hyperphenylalaninaemia and hypertyrosinaemia.
Hyperammonaemia and parenteral nutrition in infancy.
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Percutaneous central venous feeding lines in infants: do they perform as well as surgically positioned catheters?
The complications of the administration of parenteral nutrition by central venous catheter were reviewed retrospectively in 71 neonates and infants under the age of nine months. The performance of central catheters inserted by a standard surgical method was compared with that of central catheters introduced by a percutaneous insertion technique using peripheral veins and carried out on the ward. The incidence of catheter related sepsis in percutaneously inserted lines was significantly less (p less than 0.05) than in surgically inserted lines, but in all other respects, there were no significant differences in performance. These findings demonstrate that percutaneous insertion is a simple, safe and cost-effective alternative to surgical placement of feeding catheters in neonates and infants.
Hyperphenylalaninaemia in parenterally fed newborn babies.
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