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Biomedical subjects

John L D Atkinson

Publications and source records attributed to John L D Atkinson.

At least 37 records · Page 2Linked to original sources
PubMed2003

Intracranial pressure response to severe head injury induced apnea and catecholamine surge.

BACKGROUND: Apnea and catecholamine surge have been known sequelae in the first few minutes of postexperimentally induced severe head injury for over a century. However, the intracranial pressure (ICP) response to these two pathophysiologic processes is poorly understood. METHODS: We used the rat fluid percussion head injury model to study apnea and catecholamine surge separately and in combination on measured ICP response RESULTS: The three experimental groups of apnea, hypertensive surge, and both combined revealed significantly different ICP responses with markedly elevated pressures correlating closely with mean arterial blood pressure. CONCLUSION: ICP and mean arterial blood pressure correlate closely in the first few minutes after head injury in the absence of space-occupying hematomas, and may initiate pathophysiologic sequelae that can only be treated by earlier medical intervention at the scene.

Animals↗
PubMed2003

Value of diffusion-weighted imaging in patients with a nonlocalizing examination and vasospasm from subarachnoid hemorrhage.

We evaluated the value of diffusion-weighted imaging (DWI) in patients with suspected vasospasm from subarachnoid hemorrhage (SAH). Magnetic resonance imaging (MRI), including DWI, was performed in 5 patients with vasospasm resulting from SAH. Restricted diffusion (ischemia) was present in 3 patients with symptomatic vasospasm. A diffusion abnormality was not demonstrated in 2 patients with asymptomatic vasospasm despite persistently elevated velocities by transcranial Doppler ultrasonography in 1. In this patient, serial MRI studies showed no ischemia. Our results suggest that DWI may provide a method to assess the presence and severity of ischemia in patients with SAH and vasospasm and assist in patient management.

Adult↗
PubMed2003

Symptomatic vasospasm and outcomes following aneurysmal subarachnoid hemorrhage: a comparison between surgical repair and endovascular coil occlusion.

OBJECT: The authors studied patients with aneurysmal subarachnoid hemorrhage (SAH) to determine whether the incidence of symptomatic vasospasm or overall clinical outcomes differed between patients treated with craniotomy and clip application and those treated by endovascular coil occlusion. METHODS: The authors reviewed 415 consecutive patients with aneurysmal SAH who had been treated with either craniotomy and clip application or endovascular coil occlusion at a single institution between 1990 and 2000. Three hundred thirty-nine patients underwent surgical clip application procedures, whereas 76 patients underwent endovascular coil occlusion. Symptomatic vasospasm occurred in 39% of patients treated with clip application, 30% of patients treated with endovascular coil occlusion, and 37% of patients overall. Compared with patients treated with clip application, patients treated with endovascular coil occlusion were more likely to suffer acute hydrocephalus (50 compared with 34%, p = 0.008) and were more likely to harbor aneurysms in the posterior circulation (53 compared with 20%, p < 0.001). Logistic regression models controlling for patient age, admission World Federation of Neurosurgical Societies (WFNS) grade, acute hydrocephalus, aneurysm location, and day of treatment revealed that, among patients with an admission WFNS grade of I to III, endovascular coil occlusion carried a lower risk of symptomatic vasospasm (odds ratio [OR] 0.34, 95% confidence interval [CI] 0.14-0.8) and death or permanent neurological deficit due to vasospasm (OR 0.28, 95% CI 0.08-1) compared with craniotomy and clip application. Similar models revealed no difference in the likelihood of a Glasgow Outcome Scale score of 3 or less at the longest follow-up review (median 6 months) between treatment groups (OR 0.58, 95% CI 0.28-1.21). CONCLUSIONS: Patients with better clinical grades (WFNS Grades I-III) at hospital admission were less likely to suffer symptomatic vasospasm when treated by endovascular coil occlusion, compared with craniotomy and clip application. Nevertheless, there was no significant difference in overall outcome at the longest follow-up examination between the two treatment groups.

Adolescent↗
PubMed2003

Arteriovenous malformation in the trigeminal nerve. Case report.

The authors report on an arteriovenous malformation (AVM) within the trigeminal nerve in an otherwise healthy 76-year-old man who presented with the sudden onset of headache and ataxia. The AVM was totally resected via a lateral suboccipital approach to the cerebellopontine angle. Dural arteriovenous fistulas and AVMs of the dorsal root entry zone and adjacent brainstem that compress the trigeminal nerve have been previously described. To the authors' knowledge, this is the first reported case of an angiographically, surgically, and pathologically proven AVM arising from within the trigeminal nerve itself.

Aged↗
PubMed2003

Peroneal intraneural ganglia: the importance of the articular branch. Clinical series.

OBJECT: The peroneal nerve is the most common site of intraneural ganglia. The neurological deficit associated with these cysts is often severe and the operation to eradicate them is difficult The aims of this multicenter study were to collate the authors' experience with a relatively rare lesion and to improve clinical outcomes by better understanding its controversial pathogenesis. METHODS: Part I of this paper offers a description of 24 patients with peroneal intraneural ganglia who were treated by surgeons aware of the importance of the peroneal nerve's articular branch. Part II offers a description of three more patients who were seen after earlier operations in which the ganglion was excised, but the articular branch was not identified (all reportedly gross-total resections). Twenty-six of the 27 patients presented with clinical electrophysiological, and imaging evidence of a common peroneal nerve (CPN) lesion, predominantly affecting the deep peroneal nerve (DPN) division, and one patient presented with a painful mass of the CPN that was not accompanied by a neurological deficit. In all 24 patients in Part I there was magnetic resonance (MR) imaging evidence of a connection between the cyst and the superior tibiofibular joint, including one patient in whom high-resolution (3-tesla) MR neurography demonstrated the pathological articular branch itself. At the operation, the communication proved to extend through the articular branch of the CPN in all cases. The operation consisted of drainage of the cyst and ligation of the articular branch. At a minimum follow-up period of 1 year, these patients experienced significant improvements in their neuropathic pain, but only mild improvements in their functional deficits. In none of the 24 patients was there evidence of an intraneural recurrence. In three patients, however, extraneural ganglia developed: two patients with symptoms subsequently underwent resection of the superior tibiofibular joint without further recurrence and one patient with no symptoms was followed clinically after the recurrence was detected incidentally on 1-year postoperative imaging. As predicted, in Part II all three patients in whom the articular branch had not been ligated experienced early intraneural recurrence; both postoperative MR images and original studies, which were retrospectively examined, demonstrated a connection with the superior tibiofibular joint. CONCLUSIONS: The clinical presentation, electrical studies, imaging characteristics, and operative observations regarding peroneal intraneural ganglia are predictable. Treatment must address the underlying pathoanatomy and should include decompression of the cyst and ligation of the articular branch of the nerve. To avoid extraneural recurrence, resection of the superior tibiofibular joint may also be necessary, but indications for this additional procedure need to be defined. These recommendations are based on the authors' belief that intraneural peroneal ganglia arise from the superior tibiofibular joint and are connected to it by the articular branch.

Adolescent↗
PubMed2003

Peroneal intraneural ganglia: the importance of the articular branch. A unifying theory.

OBJECT: Based on a large multicenter experience and a review of the literature, the authors propose a unifying theory to explain an articular origin of peroneal intraneural ganglia. They believe that this unifying theory explains certain intriguing, but poorly understood findings in the literature, including the proximity of the cyst to the joint, the unusual preferential deep peroneal nerve (DPN) deficit, the absence of a pure superficial peroneal nerve (SPN) involvement, the finding of a pedicle in 40% of cases, and the high (10-20%) recurrence rate. METHODS: The authors believe that peroneal intraneural lesions are derived from the superior tibiofibular joint and communicate from it via a one-way valve. Given access to the articular branch, the cyst typically dissects proximally by the path of least resistance within the epineurium and up the DPN and the DPN component of the common peroneal nerve (CPN) before compressing nearby SPN fascicles. The authors present objective evidence based on anatomical, clinical, imaging, operative, and histological data that support this unifying theory. CONCLUSIONS: The predictable clinical presentation, electrical studies, imaging characteristics, operative observations, and histological findings regarding peroneal intraneural ganglia can be understood in terms of their origin from the superior tibiofibular joint, the anatomy of the articular branch, and the internal topography of the peroneal nerve that the cyst invades. Understanding the controversial pathogenesis of these cysts will enable surgeons to perform operations based on the pathoanatomy of the articular branch of the CPN and the superior tibiofibular joint, which will ultimately improve clinical results.

Cysts↗
PubMed2003

Sympathotomy instead of sympathectomy for palmar hyperhidrosis: minimizing postoperative compensatory hyperhidrosis.

OBJECTIVE: To determine whether anatomical modification of sympathectomy diminishes severe postoperative compensatory hyperhidrosis. PATIENTS AND METHODS: From January 1, 2000, to June 1, 2001, we prospectively studied 10 consecutive patients with primary palmar hyperhidrosis, aged 14 to 42 years. Medical therapy had failed in all patients. A preoperative and postoperative evaluation and thermoregulatory sweat testing were conducted in all patients. All patients underwent sympathotomy (bilateral simple disconnection) of the second thoracic ganglion input into the brachial plexus, and no sympathetic ganglia were violated. RESULTS: In the 10 patients, all 20 upper extremities improved postoperatively: 11 (55%) had near-complete cessation of palmar sweating, 8 (40%) had marked reduction in sweating, and 1 (5%) had delayed onset but full sweating at the end of the thermoregulatory sweat test. No intraoperative complications of hemopneumothorax or Horner syndrome occurred. Importantly, there were no moderate or severe postoperative hyperhidrosis complications. CONCLUSION: Sympathotomy to disconnect T2 ganglion input into the brachial plexus produces excellent results in the treatment of primary palmar hyperhidrosis and may lower the severity of postoperative compensatory hyperhidrosis complications. Long-term durability of the procedure requires further follow-up.

Adolescent↗
PubMed2003

Pulmonary complications of aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Pulmonary complications challenge the medical management of patients who have sustained aneurysmal subarachnoid hemorrhage (SAH). We assessed the frequency and types of pulmonary complications after aneurysmal SAH and analyzed the impact of pulmonary complications on patient outcome. METHODS: We reviewed the records of all patients with acute SAH treated at our institution between 1990 and 1997. Three hundred five consecutive patients with an aneurysmal hemorrhage source documented by angiography and treated within 7 days of ictus were analyzed. Outcomes at longest follow-up (mean, 16 mo) were measured by use of the Glasgow Outcome Scale. RESULTS: Pulmonary complications were documented in 66 patients (22%). The pulmonary complications were nosocomial pneumonia in 26 patients (9%), congestive heart failure in 23 (8%), aspiration pneumonia in 17 (6%), neurogenic pulmonary edema in 5 (2%), pulmonary embolus in 2 (<1%), and other pulmonary disorders in 4 (1%); 11 patients had two pulmonary complications. The incidence of symptomatic vasospasm was greater in patients with pulmonary complications (63%) than in patients without pulmonary complications (31%) (P = 0.001), and this association was independent of age and clinical grade at admission (odds ratio, 3.68; P < 0.001). Overall clinical outcomes were worse in patients with pulmonary complications (mean Glasgow Outcome Scale score, 3.3) than in patients without pulmonary complications (mean Glasgow Outcome Scale score, 4.0; P = 0.0001), but pulmonary complications were not an independent predictor of worse outcome when adjusted for age and clinical grade at admission (odds ratio, 1.38; P = 0.315). CONCLUSION: Patients who experience pulmonary complications after aneurysmal SAH have a higher incidence of symptomatic vasospasm than do patients without pulmonary complications. This most likely reflects both the failure to maintain aggressive hypervolemic and hyperdynamic therapy in patients with pulmonary compromise and the possible precipitation of congestive heart failure by hypervolemic therapy in patients with preexisting delayed ischemic neurological deficit. Although patients with pulmonary complications have worse overall clinical outcomes than do patients without pulmonary complications, this is attributable to older age and worse clinical grades at admission.

Adolescent↗
PubMed2002

Rathke cleft cyst: diagnostic and therapeutic considerations.

OBJECTIVE: To highlight diagnostic and therapeutic issues about Rathke cleft cysts for otorhinolaryngologists. STUDY DESIGN: Retrospective. METHODS: We retrospectively reviewed data collected on Rathke cleft cysts between 1978 and 1998: presenting symptoms, visual acuity, surgical treatment, complications, recurrences, and effect on daily activity. RESULTS: Twenty-nine patients were diagnosed with a Rathke cleft cyst (11 male and 18 female patients; mean age, 46 y). The most common presenting symptom was head pain (55%). The majority (59%) of cases demonstrated suprasellar extension on preoperative imaging, with pituitary dysfunction identified in 66%. Recurrence occurred in eight patients (28%). Postoperative visual function improved or remained stable in all patients. Persistent pituitary dysfunction required hormonal supplementation in seven patients (24%). Only one patient with an astrocytoma in addition to a Rathke cleft cyst did not maintain the ability to perform normally on an assessment of activities of daily living, a striking contrast to patients with craniopharyngioma. CONCLUSIONS: Conclusions were as follows: 1) Rathke cleft cysts must be considered as sources of head pain and pituitary dysfunction. 2) Persistent or recurrent cyst formation occurs in approximately one-third of the patients. Recurrence may take many years, and follow-up imaging is recommended for at least a decade. 3) Maintenance of the ability to perform the activities of normal daily living can be expected after surgical management. 4) Most Rathke cleft cysts can be managed through transnasal exposure of the sella. 5) Packing the sella may result in predisposition to recurrent cyst formation.

Activities of Daily Living↗
PubMed2002

Effects of chronic sympathectomy on locally mediated cutaneous vasodilation in humans.

In human skin, the vasodilator response to local heating includes a sensory nerve-dependent peak followed by a nadir and then a slower, nitric oxide-mediated, endothelium-dependent vasodilation. To investigate whether chronic sympathectomy diminishes this endothelium-dependent vasodilation, we studied individuals who had previously undergone surgical T(2) sympathectomy (n = 9) and a group of healthy controls (n = 8). We assessed the cutaneous vascular response (laser-Doppler) to 30 min of local warming to 42.5 degrees C on the ventral forearm (no sympathetic innervation) and the lower legs (sympathetic nerves intact). Lower body negative pressure (LBNP) was measured to confirm sympathetic denervation. During local warming in sympathectomized individuals, vascular conductance reached an initial peak at both sites [achieving 1.73 +/- 0.22 laser-Doppler units (LDU)/mmHg in the forearm and 1.92 +/- 0.21 LDU/mmHg in the leg]. It then decreased to a nadir in the innervated leg [to 1.77 +/- 0.23 LDU/mmHg (P < 0.05)] but not in the sympathectomized arm (1.69 +/- 0.21 LDU/mmHg; P > 0.10). The maximal vasodilation seen during the slower phase was not different between limbs or between groups. Furthermore, LBNP caused a 44% reduction in forearm vascular conductance (FVC) in control subjects, but FVC did not decrease significantly in sympathectomized individuals, confirming sympathetic denervation. These data indicate that endothelial function in human skin is largely preserved after sympathectomy. The altered pattern of the response suggests that the nitric oxide-dependent portion may be accelerated in sympathectomized limbs.

Adult↗
PubMed2002

Effects of chronic sympathectomy on vascular function in the human forearm.

To determine whether endothelial function is altered by chronic surgical sympathectomy, we infused ACh, isoproterenol, nitroprusside (NTP), and the nitric oxide synthase inhibitor NG-mono-methyl-L-arginine (L-NMMA) into the brachial arteries of nine patients 5-64 mo after thoracic sympathectomy for hyperhidrosis. Age- and gender-matched controls were also studied. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Lower body negative pressure was used to assess reflex vasoconstrictor responses. Tyramine, which acts locally and causes norepinephrine release from sympathetic nerves, was also administered via the brachial artery. FBF at rest was 2.5 +/- 0.4 ml x dl-1 x min-1 in the patients and 2.5 +/- 0.3 ml x dl-1 x min-1 in the controls (P = 0.95). The normal vasoconstrictor responses to lower body negative pressure were abolished in the patients. By contrast, tyramine produced dose-dependent vasoconstriction in the patients that was identical to that of controls. The dose-response curves to ACh were similar in patients and controls, with maximum values of 19.3 +/- 4.4 vs. 25.5 +/- 2.8 ml x dl-1 x min-1, respectively. L-NMMA reduced baseline FBF similarly and reduced the maximal FBF response to ACh in both groups (patients 8.9 +/- 3.5 vs. controls 9.7 +/- 2.5 ml x dl-1 x min-1). The vasodilation to isoproterenol was similar and blunted to the same extent in both groups by L-NMMA. The responses to NTP in patients and controls were similar and not affected by L-NMMA. We conclude that, in humans, chronic surgical sympathectomy does not cause major disruptions in vascular function in the forearm. The normal vasoconstrictor responses to tyramine indicate that there were viable sympathetic nerves in the forearm that were not engaged by LBNP.

Adult↗
PubMed2002

Volumetric quantification of Fisher Grade 3 aneurysmal subarachnoid hemorrhage: a novel method to predict symptomatic vasospasm on admission computerized tomography scans.

OBJECT: Predicting which patients with aneurysmal subarachnoid hemorrhage (SAH) will develop delayed ischemic neurological deficit (DIND) due to vasospasm remains subjective and unreliable. The authors analyzed the utility of a novel software-based technique to quantify hemorrhage volume in patients with Fisher Grade 3 aneurysmal SAH. METHODS: Patients with aneurysmal SAH in whom a computerized tomography (CT) scan was performed within 72 hours of ictus and demonstrated Fisher Grade 3 SAH were analyzed. Severe DIND was defined as new onset complete focal deficit or coma. Moderate DIND was defined as new onset partial focal deficit or impaired consciousness without coma. Fifteen consecutive patients with severe DIND, 13 consecutive patients with moderate DIND, and 12 consecutive patients without DIND were analyzed. Software-based volumetric quantification was performed on digitized admission CT scans by a single examiner blinded to clinical information. There was no significant difference in age, sex, admission Hunt and Hess grade, or time to admission CT scan among the three groups (none, moderate, or severe DIND). Patients with severe DIND had a significantly higher cisternal volume of hemorrhage (median 30.5 cm3) than patients with moderate DIND (median 12.4 cm3) and patients without DIND (median 10.3 cm3; p < 0.001). Intraparenchymal hemorrhage and intraventricular hemorrhage were not associated with DIND. All 13 patients with cisternal volumes greater than 20 cm3 developed DIND, compared with 15 of 27 patients with volumes less than 20 cm3 (p = 0.004). CONCLUSIONS: The authors developed a simple and potentially widely applicable method to quantify SAH on CT scans. A greater volume of cisternal hemorrhage on an admission CT scan in patients with Fisher Grade 3 aneurysmal SAH is highly associated with DIND. A threshold of cisternal hemorrhage volume (> 20 cm3) may exist above which patients are very likely to develop DIND. Prospective application of software-based volumetric quantification of cisternal SAH may predict which patients will develop DIND.

Adult↗
PubMed2002

Preoperative ventriculostomy and rebleeding after aneurysmal subarachnoid hemorrhage.

OBJECT: Despite the widespread use of ventriculostomy in the treatment of acute hydrocephalus after aneurysmal subarachnoid hemorrhage (SAH), there is no consensus regarding the risk of rebleeding associated with ventriculostomy before aneurysm repair. This present study was conducted to assess the risk of rebleeding after preoperative ventriculostomy in patients with aneurysmal SAH. METHODS: The authors reviewed the records of all patients with acute SAH who were treated at a single institution between 1990 and 1997. Thus, the records of 304 consecutive patients in whom an aneurysmal SAH source was documented on angiographic studies and who had presented to the authors' institution within 7 days of ictus were analyzed. Re-bleeding was confirmed by evidence of recurrent hemorrhage on computerized tomography scans in all cases. Forty-five patients underwent ventriculostomy for acute hydrocephalus after aneurysmal SAH at least 24 hours before aneurysm repair. Ventriculostomy was performed within 24 hours of SAH in 38 patients, within 24 to 48 hours in three patients, and more than 48 hours after SAH in four patients. The mean time interval between SAH and surgery in patients who did not undergo ventriculostomy was no different from the mean interval between ventriculostomy and surgery in patients who underwent preoperative ventriculostomy (3.6 compared with 3.8 days, p = 0.81). Fourteen (5.4%) of the 259 patients who did not undergo ventriculostomy suffered preoperative aneurysm rebleeding, whereas two (4.4%) of the 45 patients who underwent preoperative ventriculostomy had aneurysm rebleeding. CONCLUSIONS: No evidence was found that preoperative ventriculostomy performed after aneurysmal SAH is associated with an increased risk of aneurysm rebleeding when early aneurysm surgery is performed.

Acute Disease↗
PubMed2002

Far lateral extraforaminal lumbar synovial cyst: report of two cases.

OBJECTIVE AND IMPORTANCE: We present two cases of a far lateral extraforaminal synovial cyst at the L5-S1 level of the spine. Neither case was diagnosed as a synovial cyst before surgery because of their atypical location. Only one other case of an extraforaminal synovial cyst, located at L4-L5, has been reported in the literature. CLINICAL PRESENTATION: Both women presented with radicular leg pain and examination findings consistent with L5 root compression. INTERVENTION: During surgery, the cyst was not associated with the facet joint. One cyst was adherent to the nerve root. Both cysts were completely resected, with excellent pain relief. CONCLUSION: These cases serve as a stimulus to look outside the spinal canal and foramen in patients with symptoms suggesting nerve root compression. Far lateral extraforaminal synovial cyst should be included in the differential diagnosis.

Adult↗
PubMed2002

Cervical artery dissections: evidence for redissection in previously dissected arteries: report of three cases.

OBJECTIVE AND IMPORTANCE: Among patients with spontaneous internal carotid artery (ICA) or vertebral artery dissections, there is a small but significant risk of development of dissection in an uninvolved ICA or vertebral artery at some time in the future. Recurrence of dissection in a previously dissected and healed ICA or vertebral artery is very rare. We retrospectively reviewed more than 400 cases of cervical artery dissections in our cerebrovascular records for 1970 through 2000. CLINICAL PRESENTATION: Three patients with recurrence of dissection in previously dissected and presumably healed ICAs were identified. All three patients were women. Their ages at the time of the initial dissection were 42, 38, and 31 years. Initial ICA dissections were bilateral in all cases, occurring simultaneously in one case and 1 year apart in the other two cases. All dissections were spontaneous. Redissection of a previously dissected and healed ICA in these three patents occurred 11, 6, and 12 years later, respectively. Two patients had fibromuscular dysplasia. CONCLUSION: Our experience with these three cases, from among more than 400 cases of cervical artery dissections treated at our institution, and the very limited number of reported cases in the literature indicate the rarity of recurrence of dissection in previously dissected and healed cervical arteries. An underlying arteriopathy may be suspected in many of these cases. Management requires medical and sometimes surgical approaches.

Adult↗
PubMedDate not supplied

Pituitary neurologic surgery: a unique subspecialty in evolution.

OBJECTIVE: To review the evolving approaches to surgical management of pituitary tumors during the past century, which may predict future directions. METHODS: We undertook a retrospective review of selected literature published during the past century and report the trends in the treatment of pituitary tumors. RESULTS: Harvey Cushing's extraordinary influence on American neurosurgery and remarkably successful pituitary surgical series were the foundation for the development of a highly subspecialized neurosurgical operative field. Continued evolution in the treatment of pituitary tumors has been historically based on the following: (1) the development of exogenous cortisone and vasopressin; (2) the development of high-voltage and nuclear radiation therapy; (3) the experience gained from total hypophysectomy for "endocrine" driven malignant lesions and diabetic retinopathy; (4) the development of the image intensifier and television intraoperative fluoroscopic control; (5) the use of endoscopes in pituitary surgical procedures; (6) the application of the operating microscope to transsphenoidal approaches; (7) the development of the imaging modalities of computed tomographic scanning and subsequent magnetic resonance imaging; and (8) the concepts surrounding "minimally invasive" surgical techniques. CONCLUSION: The pituitary surgical techniques of today have evolved primarily because of extraordinary past accomplishments. The approaches used continue to maximize tumor resection and preserve functioning pituitary tissue. New intraoperative imaging techniques will forge the future of the field of pituitary neurosurgery, and the expected outcomes will be improved surgical success and lower perioperative morbidity.)

Cortisone↗