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Biomedical subjects

A D Sharan

Publications and source records attributed to A D Sharan.

9 recordsLinked to original sources
PubMed2001

The cause of neurologic deterioration after acute cervical spinal cord injury.

STUDY DESIGN: A retrospective review was performed to identify patients at risk for secondary neurologic deterioration after complete cervical spinal cord injury. OBJECTIVE: To examine the causes of early neurologic deterioration in patients with complete spinal cord injury at a regional spinal cord injury center. SUMMARY OF BACKGROUND DATA: After complete spinal cord injury, neurologic deterioration occurs in a subgroup of patients. Despite anecdotal reports, no study has clearly identified the subgroups at highest risks. METHODS: One hundred eighty-two patients with complete spinal cord injury were identified among 1904 consecutive patients with acute spinal trauma evaluated from March 1993 through September 1999. Parameters analyzed included demographics, mechanism of injury, American Spinal Cord Injury Association (ASIA) level on admission and during hospital stay, onset of ascension, blood pressure, hemoglobin, febrile episode, heparin administration, and the timing of operation and traction. Radiographs of patients with ascending complete spinal cord injury were reviewed with attention to fracture type and neurologic and vascular injuries. RESULTS: Twelve of 186 patients with ASIA Grade A (6.0%) complete spinal cord injury had neurologic deterioration during the first 30 days after injury. No patients with penetrating injuries had deterioration. A significant association between death and ascension was observed. The onset of ascension of the injury could be categorized into three discrete temporal subsets. Early deterioration (less than 24 hours) was typically related to traction and immobilization. Delayed deterioration (between 24 hours and 7 days) was associated with sustained hypotension in patients with fracture dislocations. Late deterioration (more than 7 days) was observed in a patient with vertebral artery injuries. CONCLUSION: Delayed neurologic deterioration in complete spinal cord injury (ASIA A) is not rare. Specific causes were identified among discrete temporal subgroups. Management of complete spinal cord injury can be improved with recognition of these temporal patterns and earlier intervention.

Adolescent↗
PubMed2001

Prevention of carotid angioplasty-induced bradycardia and hypotension with temporary venous pacemakers.

OBJECTIVE: Carotid angioplasty with stent placement is becoming an established treatment modality for patients with high-risk carotid stenosis. Unlike carotid endarterectomy, angioplasty causes direct mechanical dilation of the stenotic carotid artery and bulb. Stimulation of the sinus baroreceptors induces a reflexive response that consists of increased parasympathetic discharge and inhibition of sympathetic tone, which results in bradycardia and subsequent cardiogenic hypotension. METHODS: At a single institution, the experience with 43 patients treated from November 1994 to January 2000 with 47 angioplasty and stent procedures for occlusive carotid artery disease was retrospectively reviewed. Prophylactic temporary venous pacemakers were used to prevent hypotension from possible angioplasty-induced bradycardia. Pacemakers were set to capture a heart rate decrease below 60 beats per minute. Variables analyzed included demographics, etiology of disease, side of the lesion, the presence of symptoms, history of coronary artery disease, percent stenosis, type of stent used, number of dilations, pressure of dilation, and angioplasty balloon diameter. RESULTS: Ten patients were excluded because pacemakers were not used during their angioplasty procedures, and these included three emergencies and a lesion that was unrelated anatomically to the carotid sinus (petrous carotid). The remaining 37 procedures were performed in 33 patients with a mean age of 67 years, and consisted of 17 men, 16 women, 20 right and 17 left-sided lesions. The pacemakers maintained a cardiac rhythm in 23 (62%) of the 37 procedures and in no case did the pacemaker fail to respond when activated. Recurrent (56%; 10 of 18), radiation-induced (78%; 7 of 9), and medically refractory carotid stenosis (67%; 6 of 9) required intraprocedural pacing. Two patients with recurrent stenosis became hypotensive despite the aid of the pacing device but were not symptomatic. Seventy-nine percent (15 of 19) of symptomatic lesions and 57% (8 of 14) of nonsymptomatic lesions required pacing, which was statistically significant (P = 0.049). No patient experienced an operative morbidity or mortality as a consequence of the temporary pacing devices. CONCLUSION: Angioplasty-induced bradycardia is a common condition, and it is more prevalent in radiation-induced stenosis and with symptomatic lesions. Temporary venous demand pacing is a safe procedure and may prevent life-threatening, baroreceptor-induced hypotension.

Aged↗
PubMed2001

Single-stage autogenous bone grafting and internal fixation in the surgical management of pyogenic discitis and vertebral osteomyelitis.

OBJECT: Patients with deep wound infections complicating previously placed internal instrumentation have been successfully treated by debridement and prolonged postoperative antibiotic therapy, which avoided removal of the hardware. Comparatively fewer patients with pyogenic discitis and vertebral osteomyelitis (PDVO) have undergone single-stage debridement, arthrodesis, and internal fixation. The purpose of this study was to determine the efficacy of combining debridement, arthrodesis in which iliac autograft is used, and segmental internal fixation in a single-stage procedure for patients in whom nonoperative management of PDVO has failed. METHODS: A retrospective analysis of 17 consecutive patients with PDVO treated between July 1996 and September 1999 was performed. Follow-up data (mean 30 months) included office examinations and telephone interviews, and patients were grouped according to the duration of preoperative antibiotic therapy. All patients experienced significant postoperative reduction in pain, and those with neurological deficits improved. Eleven patients were independently ambulatory, and three required a walker; only five had been ambulating independently preoperatively. Two patients died during the 1st postoperative week of medical complications; another developed a wound dehiscence that was managed with debridement, prolonged antibiotic administration, and removal of the hardware 1 year later. In no case was pseudarthrosis demonstrated on dynamic radiography. Most patients received only a 6-week course of intravenous antibiotics postoperatively. CONCLUSIONS: The authors conclude that single-stage debridement, arthrodesis, and internal fixation can be effective in the treatment of PDVO. A 6-week course of postoperative intravenous antibiotics may be sufficient in patients with few risk factors. The harvesting of iliac autograft through the same operative exposure may not increase the risk of secondary infection.

Adult↗
PubMed2000

Epidemiology of spinal cord injury after acute odontoid fractures.

OBJECT: Cervical spinal cord injury (SCI) after odontoid fracture is unusual. To identify predisposing factors, the authors evaluated a consecutive series of patients who sustained SCI from odontoid fractures. METHODS: A consecutive series of 5096 admissions to the Delaware Valley Regional Spinal Cord Injury Center were reviewed, and 126 patients with neurological impairment at the C1-3 levels were identified. Seventeen patients had acute closed odontoid fractures with neurological deficit. Various parameters including demographics, mechanisms of injury, associated injuries, fracture types/displacements, and radiographic cervical canal dimensions were compared between "complete" and "incomplete" spinal cord injured-patients as well as with neurologically intact patients who had suffered odontoid fractures. There were similar demographics, mechanisms of injury, associated injuries, fracture type/displacement, and canal dimensions in patients with complete and incomplete SCIs. However, only patients with complete injury were ventilator dependent. In comparison with patients with intact spinal cords, spinal cord-injured patients were more commonly males (p = 0.011) who had sustained higher velocity injuries (p = 0.027). The computerized tomography scans of 11 of 17 neurologically impaired patients were compared with those of a random sample of 11 patients with intact spinal cords. Although the anteroposterior diameter (p = 0.028) and cross-sectional area (p = 0.0004) of the cervical spinal canal at the C-2 level were smaller in impaired patients, the displacement of the fragment was not different. CONCLUSIONS: Odontoid fractures are an infrequent cause of SCI. Patients with these injuries typically are males who have smaller spinal canals and have sustained high velocity injuries.

Adult↗
PubMed2000

Approaching the upper thoracic vertebrae without sternotomy or thoracotomy: a radiographic analysis with clinical application.

STUDY DESIGN: The distribution of the lowest vertebra tangential to the suprasternal notch and the lowest intervertebral disc visualized above the sternum was determined on magnetic resonance imaging (MRI) studies. The method is illustrated in seven patients undergoing upper thoracic spinal reconstruction to define a surgical approach without sternotomy or thoracotomy. OBJECTIVES: The relation of the sternal notch to thoracic vertebrae was examined by MRI to estimate the thoracic level approachable anteriorly without sternotomy. SUMMARY OF BACKGROUND DATA: Upper thoracic spine (T1-T4) visualization is considered difficult. The thoracic vertebrae that can be visualized anteriorly without sternotomy is unknown. METHODS: The vertebral level tangential to the suprasternal notch and the lowest intervertebral disc visualized in its entirety above the sternum was determined from 106 consecutive midsagittal cervicothoracic MRI studies. The method was evaluated in seven patients to illustrate application of a low suprasternal, lateral extracavitary, or transpedicular approach to performing upper thoracic reconstruction. RESULTS: The midportion of the T3 vertebra is often above the sternal notch, whereas the trajectory of the T1-T2 intervertebral disc is usually rostral to the sternum. All four patients with disease above the sternal notch on MRI underwent a low left suprasternal approach, whereas three others were treated with a lateral extracavitary or transpedicular approach. No patient worsened neurologically and all ambulated independently after surgery. CONCLUSIONS: Upper thoracic vertebrae can be exposed without sternotomy or thoracotomy by a low left suprasternal approach. Midsagittal cervicothoracic MRI can identify the thoracic vertebrae above the sternum, thereby determining whether a low suprasternal approach is feasible. Otherwise, a lateral extracavitary or transpedicular approach can be used to avoid sternotomy or thoracotomy.

Adult↗
PubMed2000

Future trends in spinal cord stimulation.

Spinal cord stimulation (SCS) has been available for about 30 years, but only in the past five years has it met with widespread acceptance and recognition by the medical community. Traditionally performed by neurosurgeons, SCS is being increasingly utilized by anesthesiologists, orthopedic surgeons and physiatrists. Pain management continues to be the most widespread application of SCS. More sophisticated technology has allowed the implanters to successfully address more complex pain syndromes such as widespread reflex sympathetic dystrophy and the failed back syndrome. Other applications are being developed, combining the ability to stimulate the spinal cord, the nerve roots and the peripheral nerves. Examples include angina pectoris, urinary incontinence and occipital neuralgia. Computer-interactive programming is gaining popularity, especially due to the extreme complexity of the implanted stimulation devices. The ability to stimulate independently multiple channels as well as multiple arrays of electrodes is today a reality. This has increased greatly the efficacy, safety and reliability of the modality. In the future, SCS will undoubtedly move several steps up in the treatment ladder of chronic pain conditions, while new applications will be discovered. The future of neural implantable technologies is bright, with an increasingly important role in the medical management of chronic conditions affecting the nervous system.

Angina Pectoris↗
PubMed2000

Internet resources for spine surgeons.

To classify web sites on common spinal disorders as to their utility for the spine surgeon and patient. Five common spinal disorders were used to generate lists of relevant sites. These sites were categorized as to their relevance for patients and surgeons, their sponsoring organization, and their comprehensiveness. A total of 56,249 web sites were found using the five key words on five search engines. Using the "And" operator, a total of 227 web sites were generated. The majority of sites were patient oriented. Physician- or organization-sponsored sites were the most common. Ten sites were found to have comprehensive information for both patients and spine surgeons. Many web sites exist that discuss disorders of the spine. Currently there is not any one web site that contains comprehensive information for both the spine surgeon and patient.

Education, Medical, Continuing↗
PubMed1995

Central nervous system tuberculosis: medical management and surgical indications.

BACKGROUND: An increase in the incidence of tuberculosis in industrialized nations has prompted a need for earlier diagnosis, treatment, and isolation of disease. An associated rise in the number of patients with central nervous system tuberculosis (CNS TB) has forced neurosurgical services to reevaluate the indications for operative intervention. METHODS: Seventeen cases of CNS TB were found in a retrospective review of all cases managed on the neurosurgical service between 1989 and 1994. These cases included eight with tuberculous meningitis, seven cases of supratentorial tuberculomas, and two cases of infratentorial tuberculomas. RESULTS: Major permanent neurologic morbidity was seen in one case (6%). Five patients (29.4%) died of complications associated with their primary disease. Eleven patients (64.6%) had excellent outcomes. All patients in the latter group completed an 18-month course of antituberculous therapy. Cerebrospinal fluid shunts were necessary in three cases and emergent craniotomy was performed in three cases. Only four cases had human immunodeficiency virus (HIV) coinfection. CONCLUSION: The neurosurgeon's role in the management of CNS TB has once again become more evident. In the present series it is unclear as to whether this is due to multiple drug-resistant strains of Mycobacterium tuberculosis or HIV coinfection. It is clear, however, that vigilance over patient compliance and serial neurologic evaluation will determine the need for operative intervention.

Adult↗