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A physiological model of the release of gas bubbles from crevices under decompression.

Moving bubbles have been observed in the blood during or after decompression using ultrasonic techniques. It has been proposed that these may grow from nuclei housed on the blood vessel wall. One candidate for bubble nucleation is hydrophobic crevices. This work explores the growth of gas pockets that might exist in conical crevices and the release of bubbles from these crevices under decompression. An existing dynamic mathematical model for the stability of gas pockets in crevices [Chappell, M.A., Payne, S.J., in press. A physiological model of gas pockets in crevices and their behavior under compression. Respir. Physiol. Neurobiol.] is extended to include the behavior as the gas pocket reaches the crevice mouth and bubbles seed into the bloodstream. The behavior of the crevice bubble is explored for a single inert gas, both alone and with metabolic gases included. It was found that the presence of metabolic gases has a significant effect on the behavior under decompression and that this appears to be due to the high diffusivity of these gases.

Algorithms↗

Minimally disruptive decompression and transforaminal lumbar interbody fusion.

BACKGROUND: Posterior spinal procedures through tubular exposures have been described. However, tubes restrain visibility and require co-axial instrument manipulation, increasing difficulty and potentially compromising surgical results. An independent-blade retractor system overcomes the obstacles of working through a tube and has been used to perform minimally-disruptive decompression and instrumented tranforaminal lumbar interbody fusion (TLIF). PURPOSE: To evaluate the advantages to patient recovery and surgical efficacy of this technique. METHODS/RESULTS: Retrospective review of technique employing a minimally-disruptive approach to decompression and transforaminal lumber interbody fusion (TLIF). CONCLUSIONS: Minimally-disruptive decompression and instrumented TLIF can be performed in a safe and effective manner using an independent-blade retractor system. Relative to traditional-open techniques, surgical goals can be accomplished, but with the benefits of minimally-disruptive surgery.

Decompression, Surgical↗

Is decompressive craniectomy for malignant middle cerebral artery territory infarction of any benefit for elderly patients?

BACKGROUND: Malignant middle cerebral artery (MCA) infarction is characterized by mortality rate of up to 80%. The aim of this study was to determine the value of decompressive craniectomy in patients who present with malignant MCA territory infarction and to compare functional outcome in elderly patients with younger patients. METHODS: Patients with malignant MCA territory infarction treated in our hospital between January 1997 and March 2003 were included in this retrospective analysis. The National Institutes of Health Stroke Scale (NIHSS) assessed neurologic status at admission, operation, and at 1 week after surgery. All patients were followed up for assessment of functional outcome by the Barthel Index (BI) and the modified Rankin Scale (RS) at 3 to 9 months after infarction. RESULTS: Twenty-five patients underwent decompressive craniectomy. The mortality was 7.7% in younger patients (ages <60 years) compared with 33.3% in elderly patients (ages >/=60 years) (P > .05). All patients had significant decrease of NIHSS after surgery (P < .001). At follow-up, younger patients who received surgery had significantly better outcome with mean BI of 75.42 and Rankin score of 3.00; however, none of the elderly survivors had a BI score above 60 or a Rankin score below 4. CONCLUSION: Decompressive craniectomy in younger patients with malignant MCA territory infarction improves both survival rates and functional outcomes. Although survival rates were improved after surgery in elderly patients, functional outcome and level of independence were poor.

Age Factors↗

Long-term results for liver transplantation from non-heart-beating donors maintained with chest and abdominal compression-decompression.

INTRODUCTION: The aim of this study was to evaluate long-term results after liver transplantation from non-heart-beating donors (NHBD) using the method of chest and abdominal compression-decompression to maintain donors. METHODS: From December 1995 to November 2004, 10 NHBD were identified and maintained by means of the method of chest and abdominal compression-decompression until family and judicial permission were granted. Nine donors were Maastricht type II and one was type IV. RESULTS: The mean age of donors was 40.5 years and the mean time under cardiopulmonary resuscitation (CPR) was 80 minutes. Orthotopic liver transplantation (OLT) was performed using these 10 liver grafts after a mean cold ischemia time of 561.5 minutes. All patients developed good posttransplant function, except for one patient who presented with primary nonfunction corrected with retransplantation. This complication was directly related to a long CPR time (P < .01). After a mean follow-up of 57 months, only one patient died from a hepatitis C virus (HCV) recurrence. The rest of the patients have maintained good graft function over time. CONCLUSIONS: NHBD maintained with the method of chest and abdominal compression-decompression are a valid choice to increase the donor pool. Liver transplantation using these grafts has proven good long-term results, comparable to their heart-beating counterparts.

Adult↗

Resolution of papilledema after neurosurgical decompression for primary Chiari I malformation.

PURPOSE: To report a causal relationship between Chiari I malformation and its rare, but recognized manifestation of bilateral papilledema. DESIGN: Interventional case series. METHODS: Four adult female patients (mean age, 48, age range 25-59 years) with bilateral papilledema, signs and symptoms of increased intracranial pressure, and cranial magnetic resonance imaging (MRI) evidence of a Chiari I malformation ranging from 7 to 22 mm of tonsillar herniation underwent suboccipital decompression. RESULTS: In all four patients, suboccipital decompression was followed by resolution of bilateral papilledema and signs and symptoms of increased intracranial pressure. CONCLUSION: Patients with bilateral papilledema and presumed pseudotumor cerebri require a cranial MRI to determine if they have a Chiari I malformation, because patients with increased intracranial pressure and papilledema from a Chiari I malformation may benefit from suboccipital decompression.

Adult↗

Resolution of acute acquired comitant esotropia after suboccipital decompression for Chiari I malformation.

PURPOSE: To report a case of acute comitant esotropia successfully treated with suboccipital decompression in a 9-year-old male patient with Chiari I malformation. DESIGN: Interventional case report. METHODS: A 9-year-old male with Chiari I malformation had acute onset of diplopia, headache, and comitant esotropia. RESULTS: About 9 months after suboccipital decompression, diplopia resolved and there was near orthophoria on examination 15 months after surgery. CONCLUSION: In view of our case and after a review of literature, we advocate primary suboccipital decompression to treat acute comitant esotropia in patients with Chiari I malformation. A follow-up period of at least 1 year rather than 6 months seems necessary to assess surgery effects.

Acute Disease↗

A new approach to left heart decompression.

A simple, safe, indirect technique for decompression of the left heart is described. Pulmonary artery venting produces immediate and total decompression of the left heart through spontaneous retrograde pulmonary flow across the open mitral valve in the hypothermic (29 degrees C) electrically fibrillated heart. This allows free retrograde flow of left heart blood across the pulmonary valve into the right ventricle, where it is taken up by the usual caval cannulas. In 25 of 66 consecutive patients undergoing elective ventricular fibrillation and anoxic arrest, left heart venting was necessary as indicated by rising left heart pressures. Total cardiac decompression was immediately and completely achieved by this simple indirect technique. Direct left heart venting, with its associated risks and disadvantages, was never necessary, and we now consider it obsolete.

Cardiac Catheterization↗

Decompression of fetal cardiac tamponade caused by congenital capillary hemangioma of the pericardium.

BACKGROUND: Isolated fetal pericardial effusion is rare but has been associated with various cardiac masses. Decompression in utero might prolong the pregnancy. CASE: In a 34-year-old white woman, gravida 3, para 0-1-1-1, at 34 5/7 weeks' gestation, ultrasound detected massive fetal pericardial effusion that progressed rapidly to hydrops. The fetal heart was structurally normal. We decompressed the fetal cardiac tamponade by pericardiocentesis, removing 52 mL of straw-colored fluid, which improved fetal movement and hydrops. We did pericardiocentesis at 6 weeks postpartum for a large pericardial effusion. Two weeks later the effusion recurred and we did thoracotomy with pericardial window placement. Pathologic diagnosis of pericardial biopsy was congenital capillary hemangioma of the pericardium. CONCLUSION: Isolated fetal pericardial effusion can be caused by capillary hemangioma of the pericardium despite lack of any mass on ultrasound. Decompression of pericardial effusion in utero might relieve fetal cardiac tamponade and extend pregnancy.

Adult↗

Ureterocele causing anhydramnios successfully treated with percutaneous decompression.

BACKGROUND: Ureteroceles are congenital cystic dilatations of the submucosal segment of the distal ureter. We present a case of an intravesical ureterocele causing anhydramnios at 31 weeks' gestation. CASE: A primiparous woman near 20 weeks' gestation had ultrasound evidence of a fetal duplicated right collecting system. At 31 weeks, an intravesical ureterocele was seen along with bilateral hydroureteronephrosis and anhydramnios. A single percutaneous needle decompression of the bladder and ureterocele successfully restored amniotic fluid volume. CONCLUSION: Follow-up ultrasounds are indicated when either a duplicated renal collecting system or a ureterocele is identified. In utero treatment is indicated only when amniotic fluid is compromised. Needle decompression should be first-line treatment, with more invasive methods reserved for failures of decompression.

Decompression, Surgical↗

Is decompressive craniectomy for acute cerebral infarction of any benefit?

BACKGROUND: Acute occlusion of the major cerebral arteries results in ischaemic changes to the brain, without time for reperfusion by the collateral circulation. The subsequent cellular events lead to a breakdown of the blood-brain barrier, causing malignant cerebral edema manifested clinically by a rapid neurological deterioration. The aim of this study was to determine the value of surgical decompression in patients who present with acute cerebral infarction. METHODS: Retrospective review of patients with deteriorating consciousness level from massive cerebral ischemia and secondary edema, treated by decompressive craniectomy. RESULTSThere were 10 patients over a 2-year period from 1997-99, consisting of seven male and three female patients (mean age 47.56 years) with a mean preoperative Glasgow Coma Scale (GCS) score of 6/15. Three patients had dominant middle cerebral artery (MCA) infarction, four had nondominant MCA infarction, one had posterior cerebral artery infarction, and the remaining two had cerebellar infarction. At a mean follow-up period of 7 months, two patients had died (20% mortality), four patients (40%) were vegetative or severely disabled, and the remaining four patients (40%) had mild disability or good outcome. Favorable prognostic factors were younger age (less than 50 years) and good initial GCS score (14 or better). CONCLUSION: Decompressive craniectomy in the setting of acute brain swelling from cerebral infarction is a life-saving procedure and should be considered in younger patients who have a rapidly deteriorating neurologic status.

Adult↗

Pathological evaluation of intervertebral disc tissue specimens after routine cervical and lumbar decompression. A cost-benefit analysis retrospective study.

BACKGROUND: After decompression of cervical and lumbar nerve roots for radicular pain, pathological evaluation of the extracted disc material is commonly performed. Although histological examination rarely detects clinically significant unsuspected disease, it remains a common practice in most hospitals in the United States. To determine the cost-effectiveness of this routine practice, we conducted a retrospective study. The results are contained within this report. METHODS: Using the University Neurosurgery database, we retrospectively identified 1,387 patients who had spinal decompression surgery (laminectomy and/or discectomy). These cases were broadly classified into routine and non-routine cases depending on the preoperative diagnosis. Benign and noninfectious cases were classified as routine; malignant and all other cases were classified as nonroutine. We reviewed the medical records and pathology reports of these routine and nonroutine cases in an attempt to study the efficacy of the pathological evaluation of the disc material. The cost-benefit value of histopathology in these cases was analyzed, retrospectively. RESULTS: In all routine cases, the histopathology was consistent with benign disc disease and yielded no additional information that could have altered the treatment plan. In the nonroutine cases, however, histopathology was significant in the management of the patient. The cost factor for pathological study was the same for both case groups. CONCLUSIONS: Pathological study of intervertebral disc specimens is cost beneficial only in cases with significant preoperative clinical diagnoses. Pathological evaluation of routine herniated nucleus pulposus extracted during decompressive surgeries is not warranted.

Cervical Vertebrae↗

Microvascular decompression for trigeminal neuralgia in patients with multiple sclerosis.

BACKGROUND: Microvascular decompression (MVD) of the trigeminal nerve is a well-established procedure for the treatment of idiopathic trigeminal neuralgia. Multiple sclerosis (MS) has long been considered a contraindication for this procedure, due to the known polycentric nature of the disease. Medical treatment followed by percutaneous procedures provide relief for the great majority of these patients. There exists a small subgroup of patients with trigeminal neuralgia who are diagnosed with MS only after a microvascular decompression procedure has been performed. Furthermore, management of the patient with known MS whose pain continues to recur, despite maximal medical therapy and multiple percutaneous procedures, can be exceedingly difficult. METHODS: Five patients with MS, three who had undergone multiple unsuccessful percutaneous procedures and two in whom the diagnosis of MS had not been established, underwent exploration of the cerebellopontine angle. Three patients underwent MVD alone, and two (both with known MS) underwent MVD and partial section of the trigeminal nerve. RESULTS: Patients who underwent microvascular decompression alone did not have satisfactory relief of pain. Patients who underwent partial sectioning of the nerve did better. CONCLUSIONS: Patients with MS and symptoms of typical trigeminal neuralgia may benefit from exploration of the cerebellopontine angle and partial sectioning of the nerve. MVD alone fails to provide adequate or reliable relief of pain.

Adult↗

Surgical treatment of benign intracranial hypertension--subtemporal decompression revisited.

BACKGROUND: Subtemporal decompression, first advocated by Dandy for the treatment of benign intracranial hypertension or pseudotumor cerebri, has been replaced as a treatment mainstay by medical management using diuretics, steroids, and lumbar puncture. Failure of these forms of treatment has frequently led to insertion of cerebrospinal fluid shunts. METHODS: We have retrospectively reviewed the long term outcome of eight patients who were treated by subtemporal decompression (STD) for classical presentations of refractory benign intracranial hypertension. The follow-up period ranged from 8 to 26 years. RESULTS: Within 1 month of STD, deterioration in visual fields and acuity resolved in all eight patients. Five of eight patients required CSF diversion procedures after subtemporal decompression to control headaches. No patient experienced recurrent permanent visual deterioration after STD. CONCLUSION: STD may be the most effective treatment in both long and short term follow-up to provide lasting relief and prevention of visual morbidity caused by refractory benign intracranial hypertension.

Adolescent↗

Functional outcome and the effect of cranioplasty after retromastoid craniectomy for microvascular decompression.

BACKGROUND: While the efficacy of retromastoid craniectomy for microvascular decompression for hyperactive cranial nerve syndromes is well established, there is no real information regarding the functional outcome of these operations. The purpose of this retrospective questionnaire study is to assess functional outcome regarding presence and duration of postoperative headache, incisional pain, and the time to return to normal activity in patients undergoing retromastoid craniectomy for microvascular decompression. The effect of closure with bone chips or cranioplasty in the defect upon these functional outcomes was studied, as was the influence of the particular nerve that was the object of decompression. METHODS: Four-hundred and ninety-five consecutive patients were contacted and 320 (65%) returned questionnaires with enough information to be suitable for analysis. RESULTS: The incidence of postoperative headache was initially 60.1%, dropping to 28.8% at 1 month and 16.8% at 6 months. Incisional pain likewise declined with time, noted in 25.8% at 1 month and only 13.1% at 6 months. Use of a cranioplasty made no significant difference in influencing either postoperative headache or incisional pain, nor was the nature of the procedure a significant factor. CONCLUSION: Twenty-five percent of patients resumed normal activity by 3 weeks, 50% by 1 month, and 90% by 3 months. Overall, 98% of patients responding reported returning to normal activity. Therefore, although there is an incidence of postoperative headache and incisional pain, these decrease with time and do not seem to interfere with the return to normal activity, nor are they affected by placement of a cranioplasty or the nature of the operation.

Activities of Daily Living↗

Facial canal decompression leads to recovery of combined facial nerve paresis and trigeminal sensory neuropathy: case report.

BACKGROUND: Trigeminal sensory neuropathy is often associated with facial idiopathic nerve paralysis (Bell's palsy). Although a cranial nerve viral polyneuropathy has been proposed as the usual cause, in many instances the etiology remains unclear. This case report of recovery of both trigeminal and facial neuropathy after surgical decompression of the facial nerve suggests an anatomic link. METHODS: A case of a 39-year-old woman presenting with recurrent unilateral facial paralysis is summarized. Her fifth episode, which did not spontaneously recover, was associated with retroorbital and maxillary pain as well as sensory loss in the trigeminal distribution. RESULTS: A middle cranial fossa approach for decompression of the lateral internal auditory canal, labyrinthine segment of the facial nerve and the geniculate ganglion was performed. The patient's pain and numbness resolved immediately postoperatively, and the facial paralysis improved markedly. CONCLUSION: This result implicates a trigeminal-facial reflex as hypothesized by others. It suggests that decompression of the facial nerve can lead to improvement in motor and sensory function as well as relief of pain in some patients with combined trigeminal and facial nerve dysfunction.

Adult↗

Retrograde suction decompression of paraclinoid aneurysm--a revised technique.

BACKGROUND: Aneurysms of the ophthalmic segment of the carotid artery are difficult lesions to handle. Batjer and Samson described the technique of suction decompression of the aneurysm by inserting a needle and aspirating blood from the internal carotid artery in the neck. However, this method carries a risk of arterial dissection and distal embolization. METHOD: We describe a revised technique for suction decompression of paraclinoid aneurysms. The method makes use of the anatomical advantage of the carotid bifurcation. Instead of direct clamping of the internal carotid artery, we isolated the common and external carotid arteries and decompressed the aneurysm via the external carotid artery. We also saved the aspirated blood for autotransfusion. RESULTS: We have used this technique in two elderly patients with good results. CONCLUSION: This technique avoids dissection of the internal carotid artery and minimizes the risk of embolization.

Blood Loss, Surgical↗

Graded orbital decompression based on severity of proptosis.

OBJECTIVE: To study the results of orbital decompression based on the severity of preoperative proptosis. DESIGN: A retrospective noncomparative interventional case series. PARTICIPANTS: Thirty-nine orbits in 23 patients with thyroid-related orbitopathy at a university-based referral center. INTERVENTION: Graded orbital decompression was performed in all patients based on the severity of preoperative exophthalmometry. MAIN OUTCOME MEASURES: Exophthalmometry, visual acuity, margin-to-reflex distance, prism cover testing, and intraocular pressure. RESULTS: Mean proptosis reduction in all orbits was 6.4 +/- 2.7 mm (P < 0.01). In group 1 (preoperative exophthalmometry <22 mm), proptosis decreased with a mean of 4.8 +/- 1.3 mm (P < 0.01); mean proptosis reduction was 6.0 +/- 2.3 mm (P < 0.01) and 8.9 +/- 3.4 mm (P < 0.01) in group 2 (exophthalmometry between 22-25 mm) and group 3 (exophthalmometry >25 mm), respectively. In four of five eyes with compressive optic neuropathy there was an improvement of best-corrected visual acuity of 2 lines or more. Margin-to-reflex distance of the upper and lower lids and intraocular pressure were reduced in all groups. New-onset diplopia developed in two patients (8.7%); 13 of 15 patients (86.7%) who had diplopia preoperatively had persistent diplopia postoperatively. Two patients (13.3%) had relief of diplopia postoperatively. CONCLUSIONS: Graded orbital decompression based on the severity of preoperative exophthalmometry is useful to determine the type and amount of orbital surgery to be performed.

Adult↗

Corticosteroids in treatment of serious decompression sickness.

Although high-dose corticosteroids have been widely recommended as an adjunctive measure in the treatment of serious decompression sickness, there are few objective data to support their efficacy in this disease. An unusual case of neurological decompression sickness which seemed to demonstrate a therapeutic response to steroids independent of recompression is presented. The various manifestations of decompression sickness and the effectiveness of delayed treatment are discussed.

Adrenal Cortex Hormones↗