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Strabismus after balanced medial plus lateral wall versus lateral wall only orbital decompression for dysthyroid orbitopathy.

PURPOSE: This study aimed to determine the relative incidence and time course of new-onset strabismus after balanced medial plus lateral wall orbital decompression versus decompression of the lateral wall alone for dysthyroid orbitopathy. METHODS: The study design was a retrospective nonrandomized comparative case series. Thirty-two consecutive patients underwent balanced medial plus lateral wall orbital decompression or lateral wall orbital decompression for dysthyroid orbitopathy. The incidence, duration, and treatment of postoperative strabismus was recorded for each patient. RESULTS: Significant preoperative strabismus was present in 31% (4/13 patients) of the balanced decompression group and in 26% (5/19 patients) of the lateral wall decompression group. Only 25% (1/4) of cases of preexisting strabismus in the balanced decompression group resolved postoperatively without muscle surgery, whereas 60% (3/5) of cases in the lateral wall decompression group resolved postoperatively without surgery. Preoperative strabismus was absent in 69% (9/13) of patients in the balanced decompression group and in 74% (14/19) of patients in the lateral wall decompression group. New-onset, persistent postoperative strabismus developed in 33% (3/9) of patients in the balanced decompression group and in 7% (1/14) of patients in the lateral wall decompression group. CONCLUSION: Lateral wall orbital decompression may produce less new-onset, persistent postoperative strabismus than balanced medial plus lateral wall orbital decompression for dysthyroid orbitopathy.

Adult↗

Active compression-decompression resuscitation: analysis of transmitral flow and left ventricular volume by transesophageal echocardiography in humans. Cardiopulmonary Resuscitation Working Group.

OBJECTIVES: This study was designed to test the hypothesis that active compression-decompression cardiopulmonary resuscitation increases transmitral flow and end-decompression left ventricular volume over levels achieved with standard manual cardiopulmonary resuscitation. BACKGROUND: Recently, cardiopulmonary resuscitation incorporating active compression and decompression of the chest has been demonstrated to improve hemodynamic status in a canine model and in humans after cardiac arrest. METHODS: The active compression-decompression device was applied midsternum in five consecutive patients and results compared sequentially (in random order) with those of standard manual cardiopulmonary resuscitation. Both techniques were performed at 80 compressions/min with a 1.5- to 2-in. (3.8 to 5.1 cm) compression depth and a 50% duty cycle. Transesophageal echocardiographic data obtained in each patient included the velocity-time integral of transmitral pulsed Doppler recordings and two-dimensional images of the left ventricle in the long-axis view. Planimetric volume measurements of the left ventricle were obtained at both end-compression and end-decompression. RESULTS: No difference was observed in end-compression volume between the two techniques (p = 0.81). Increased end-decompression volume (active compression-decompression technique 81.3 +/- 12.5 vs. standard technique 69.4 +/- 10.8, p < 0.05), stroke volume (active compression-decompression technique 32.6 +/- 6.8 vs. standard technique 17.6 +/- 5.2, p < 0.05) and velocity-time integral of transmitral flow (active compression-decompression technique 15.8 +/- 4.3 vs. standard technique 7.8 +/- 2.3, p < 0.05) were found in the active compression-decompression group. The transmitral velocity-time integral was highly correlated with left ventricular stroke volume (r = 0.90). CONCLUSIONS: Improved transmitral flow, end-decompression left ventricular volume and stroke volume are seen with active compression-decompression resuscitation, suggesting a biphasic cardiothoracic cycle of flow. Active decompression of the chest appears to be a beneficial adjunct to standard cardiopulmonary resuscitation.

Aged↗

The incidence of diplopia following coronal and translid orbital decompression in Graves' orbitopathy.

PURPOSE: Firstly, to assess the incidence of induced diplopia following orbital decompression in patients with Graves' orbitopathy. Secondly, to assess patient satisfaction after orbital decompression. Thirdly, to determine the factors that contribute to the variable reported incidence of diplopia complicating decompression surgery. METHODS: We present a retrospective analysis of the alterations of ocular motility in a consecutive series of 81 patients with Graves' orbitopathy who underwent orbital decompression by either a coronal or a translid approach. We assessed patient satisfaction by a telephone survey, and we reviewed the literature. RESULTS: Eleven patients underwent decompressive surgery for dysthyroid optic neuropathy (DON); 5 of them had a three-wall coronal decompression, the other 6 had a two-wall translid decompression. One of the 5 (20%) coronal versus 2 of the 6 (33%) traslid patients experienced worsening of their existing diplopia. Seventy patients underwent surgery for disfiguring proptosis; 41 of them had a coronal decompression and 29 had a translid decompression. Eight of the 41 coronal patients (20%) and 4 of the 29 translid patients (14%) experienced aggravation of their motility impairment. There was no statistically significant difference between these percentages (chi-squared, p > 0.05). Three of 26 coronal patients (12%) without pre-operative motility impairment developed diplopia in all directions. Twenty-five per cent needed strabismus surgery (9% multiple times). High satisfaction scores were noted after both types of orbital decompression. Through a review of the literature, several factors that may add to heterogeneous results were identified, including definition of diplopia, inclusion criteria and type of surgery. CONCLUSIONS: Induced diplopia is seen after any type of orbital decompression (19% overall), and its incidence is determined by various factors. To facilitate comparative studies between decompression techniques, a standardised protocol for orthoptic evaluation should be developed.

Adult↗

The detection of gas bubbles in guinea-pigs after decompression from air saturation dives using ultrasonic imaging.

1. Bubble formation in the hind limb of anaesthetized guinea-pigs, after decompression from two different saturation exposures to air, 0.69 and 0.83 MPa gauge, has been studied using an ultrasonic pulse--echo imaging technique. 2. A qualitative analysis of the bubble formation, observed over a 30 min period after decompression, showed that profuse, largely stationary bubble formation occurred within 3 min of the decompression from 0.83 MPa gauge but that extensive stationary bubble formation was not observed until 17 min after decompression from 0.69 MPa gauge. Electrocardiogram changes appeared coincidently with the appearance of major bubble formation after the 0.83 MPa decompression but after the 0.69 MPa decompression changes were not observed until the end of the 30 min surveillance period, considerably later than the occurrence of a large number of bubbles. 3. A quantitative analysis of the echo patterns recorded during the 60 sec decompression and for 60 sec after the decompression demonstrated that the increase in severity of the decompression corresponded to an increase of 152% in the number of bubbles observed. The echoes observed during this period have been identified as either transient or persistent and their distribution of size, location and times of appearance and duration have been described. 4. From the quantitative analysis approximate estimates of the contribution by mobile, intravascular gas bubbles to the elimination of the excess gas have been made. These estimates range from 0.01 to 0.9% after the 0.69 MPa decompression and from 0.06 to 6% after the 0.83 MPa decompression. 5. It is concluded that the pulse--echo ultrasonic imaging technique provides a powerful means of analysing the distributions of bubble formation, both qualitatively and quantitatively, after decompression; it has the important attribute of being able to monitor both moving and stationary bubbles simultaneously in a variety of tissue types.

Animals↗

Single-level posterolateral arthrodesis, with or without posterior decompression, for the treatment of isthmic spondylolisthesis in adults. A prospective, randomized study.

Forty-two neurologically intact adults in whom non-operative treatment of grade-I or grade-II isthmic spondylolisthesis of the most caudad lumbar segment had failed were entered into a prospective study of the results of operative treatment. Twenty patients who smoked were managed with a posterolateral arthrodesis with instrumentation (transpedicular fixation), and twenty-two patients who did not smoke were managed with a posterolateral arthrodesis without instrumentation. Of the patients who were managed with instrumentation, eight were randomized to treatment with a decompressive laminectomy and twelve, to treatment without it; in the group that was managed without instrumentation, the distribution was ten and twelve patients, respectively. The patients were followed clinically for a mean of 4.5 years (range, 3.5 to six years). Of the eighteen patients who had been managed with decompression, four had a pseudarthrosis and six had an unsatisfactory result compared with none and one of the twenty-four who had been managed without decompression (p = 0.02 and p = 0.01, respectively). In the group of twenty patients (smokers) who had been managed with instrumentation, none of the twelve managed without decompression had a pseudarthrosis compared with one of the eight managed with decompression (p = 0.2). In the group of twenty-two patients (non-smokers) who had been managed without instrumentation, none of the twelve managed without decompression had a pseudarthrosis compared with three of the ten managed with decompression (p = 0.04). In the group managed with instrumentation, two of the eight who had had decompression had an unsatisfactory result compared with none of the twelve who had not had decompression. In the group managed without instrumentation, four of the ten who had had decompression had an unsatisfactory result compared with one of the twelve who had not had decompression. The addition of decompression to arthrodesis, performed with or without instrumentation, for the treatment of low-grade isthmic spondylolisthesis in patients who do not have a serious neurological deficit does not appear to improve the result and may significantly increase the rates of pseudarthrosis and unsatisfactory results.

Adult↗

Serial measurement of portal hemodynamics after partial portal decompression.

In a serial analysis of splanchnic hemodynamics, we compared partial with total portal decompression in 16 alcoholic cirrhotic patients who underwent portacaval shunts for variceal hemorrhage. Partial decompression was achieved with 8 or 10 mm polytetrafluorethylene portacaval H grafts and aggressive collateral ligation. Total decompression was achieved with larger diameter H grafts (12 or 14 mm). Early and follow-up (mean interval, 18 months) postoperative studies of portal hemodynamics included: direct measurement of shunt gradients, scintigraphic quantitation of portal and mesenteric flow distribution to the liver, and a portal and splenic collateral scoring system developed from standardized splenic venography. Partial portal decompression reduced portal pressure by 43% +/- 8% compared with 81% +/- 5% after total decompression (p less than 0.01). Scintigraphy demonstrated that partial decompression provided a greater fraction of portal flow to the liver than did total decompression (57% +/- 9% versus 2% +/- 1% intrahepatic radioactivity) and mesenteric flow distribution (14.5% +/- 5.4% versus 1.2% +/- 0.7%). Only one patient with partial decompression had a significant loss of portal perfusion during the interval studies. Significantly more residual collaterals were visualized in patients with partial decompression than in those with total decompression, and interval studies showed no significant changes from early studies. We conclude that partial decompression maintains higher portal pressures, more residual collaterals, and a greater fraction of portal and mesenteric flow to the liver than does total decompression. A modest but uniform reduction of portal pressure minimizes stimulus for new collateral formation and further shunting of portal flow.

Collateral Circulation↗

Orbital decompression for Graves' disease. Exposure through lateral canthal and inferior fornix incision.

A surgical procedure is described to perform orbital decompression in patients suffering from orbitopathy in Graves' Disease. The decompression technique employs exposure of the orbit through a lateral incision and an inferior fornix incision. These combined incisions with exposure can be used to perform an antral-ethmoidal decompression (two-wall decompression) or an antral-ethmoidal-lateral wall decompression (three-wall decompression). This present series contains 34 patients who underwent decompression through a 2 1/2-year period ending October 1980. The results of decompression were quantitated by measuring the retroplacement of the globe and in patients with compressive optic neuropathy by improvement in vision. The retroplacement of the globe with the antral-ethmoidal (two-wall decompression) was 4 to 7 mm (average 6 mm), and the retroplacement was 6 to 8 mm in four patients who underwent antral-ethmoidal-lateral decompression (three-wall decompression). All patients with compressive optic neuropathy improved to a final visual acuity of 20/40 or better. Five of 11 patients, with compressive optic neuropathy required postoperative super-voltage irradiation to reach this acuity. Fifty percent of the patients undergoing antral-ethmoidal decompression for proptosis required additional eyelid surgery with recession of upper lid retractors.

Adult↗

Right-to-left shunt and risk of decompression illness with cochleovestibular and cerebral symptoms in divers: case control study in 101 consecutive dive accidents.

OBJECTIVE: We investigated the role of right-to-left shunt with standardized transcranial Doppler ultrasonography in a large population of divers referred for symptoms of decompression illness. DESIGN: Case series compared with a control group. SETTING: Military teaching hospital, hyperbaric unit. PATIENTS: Patients were 101 consecutive divers with clinical evidence of decompression illness and a control group of 101 healthy divers. INTERVENTION: Specification of the type of decompression illness involved and detection/evaluation of right-to-left shunt by standardized transcranial Doppler. The degree of right-to-left shunt was defined as major if the number of high-intensity transient signals in the middle cerebral artery was >20. MEASUREMENTS AND MAIN RESULTS: We evaluated the odds ratios by logistic regression analysis with vs. without right-to-left shunt for subjects with cochleovestibular symptoms, cerebral decompression illness, spinal decompression illness, and Caisson sickness. Of the 101 divers presenting with decompression illness, transcranial Doppler detected a right-to-left shunt in 59 (58.4%), whereas control subjects demonstrated a right-to-left shunt in 25 cases (24.8%; odds ratio, 4.3; 95% confidence interval, 2.3-7.8; p=.09). When a right-to-left shunt was detected, the right-to-left shunt was major in 12 of 25 patients in the control group and in 49 of 59 patients in the decompression illness group (odds ratio, 8.7; 95% confidence interval, 4.2-18.0; p<.001). Within the decompression illness group, the proportion of major right-to-left shunt was 24 of 34 (odds ratio, 29.7; 95% confidence interval, 10.0-87.2; p<.0001) in the cochleovestibular subgroup, 13 of 21 (odds ratio, 24.1, 95% confidence interval, 6.8-86.0, p< 0.0001) in the cerebral decompression illness subgroup, ten of 31 (odds ratio, 3.9; 95% confidence interval, 1.5-10.3; p<.01) in the spinal decompression illness subgroup, and two of two (odds ratio, 1.1; 95% confidence interval, 0.2-5.7; p=.9) in the subgroup of divers with Caisson sickness. CONCLUSION: Based on our results, we conclude that major right-to-left shunt was associated with an increased incidence of cochleovestibular and cerebral decompression illness, suggesting paradoxical embolism as a potential mechanism.

Adult↗

Role of postoperative magnetic resonance imaging after microvascular decompression of the facial nerve for the treatment of hemifacial spasm.

OBJECTIVE: This study was performed to investigate the role of postoperative three-dimensional short-range magnetic resonance angiography in the prediction of clinical outcomes after microvascular decompression (MVD) for the treatment of hemifacial spasm. METHODS: We examined pre- and postoperative magnetic resonance imaging scans obtained between March 1999 and May 2000 for 122 patients with hemifacial spasm, to evaluate the degree of detachment of the vascular contact and changes in the positions of offending vessels. The degree of vascular decompression of the facial nerve root was classified into three groups, i.e., contact, partial decompression, or complete decompression. Contact was defined as unresolved compression, as indicated by postoperative three-dimensional short-range magnetic resonance angiography. Partial decompression was defined as incompletely resolved compression; vascular indentation of the facial nerve was improved, but contact with the facial nerve remained. Complete decompression was defined as completely resolved compression. These findings were compared with the surgical findings and clinical outcomes. RESULTS: Of 122 patients with MVD, complete decompression of offending vessels at the root entry zone of the facial nerve was observed for 106 patients (86.9%), partial decompression was observed for 10 patients (8.2%), and contact with offending vessels was observed for 6 patients (4.9%) by using postoperative three-dimensional short-range magnetic resonance angiography. Our study demonstrated that the types of offending vessels affected neither the degree of decompression of the root entry zone of the facial nerve nor surgical outcomes (P > 0.05). Also, there was no significant relationship between the degree of decompression and improvement of symptoms (P > 0.05). Furthermore, there was no significant relationship between the degree of decompression and the timing of symptomatic improvement (P > 0.05). CONCLUSION: Our data suggest that MVD of the facial nerve alone may not be sufficient to resolve symptoms for all patients with hemifacial spasm. Therefore, unknown factors in addition to vascular compression may cause symptoms in certain cases, and it may be necessary to remove those factors, simultaneously with MVD, to obtain symptom resolution.

Adult↗

Scoliosis associated with Chiari 1 malformations: the effect of suboccipital decompression on scoliosis curve progression: a preliminary study.

STUDY DESIGN: A retrospective review of the effect of suboccipital decompression and duraplasty on curve progression in 22 patients who presented with scoliosis, syringomyelia, and a Chiari 1 malformation. OBJECTIVES: To document the clinical characteristics of scoliosis in association with a Chiari 1 malformation, determine the effects of suboccipital decompression and duraplasty on scoliosis curve progression over time, and identify the clinical factors (age, gender, and curve characteristics) that may be associated with a clinical improvement in the scoliotic deformity after suboccipital decompression. SUMMARY OF BACKGROUND DATA: Prior publications have documented the clinical characteristics, signs, and symptoms of the Chiari 1 malformation. An association between Chiari 1 malformations, syringomyelia, and scoliosis has been recognized and reported. Several authors have also reported on the response of the scoliotic curve to Chiari 1 decompression, but the number of patients in these reports has been small. This cohort represents the largest number of patients to date (21) with Chiari 1 malformations, syringomyelia, and scoliosis who have been treated and followed over time in order to determine the effect of decompression on curve progression. METHODS: A retrospective case review of 85 patients, age 16 years or less, who underwent posterior fossa decompression for a Chiari 1 malformation between 1990 and November 2000. A subset of 7 males and 15 females (22 of 85 total patients) who initially presented with scoliosis and were then found to have a Chiari 1 malformation was selected from this larger cohort for further review. The orthopedic and neurosurgical charts, spinal radiographs, and magnetic resonance imaging scans were then reviewed for each of these patients. RESULTS: Twenty-one of the 22 patients who presented with scoliosis met the inclusion criteria of having a Chiari 1 malformation, scoliosis, and an unfused spine during the follow-up period after suboccipital decompression. One patient had a posterior spinal fusion before suboccipital decompression and was excluded from further review. CONCLUSIONS: Thirteen patients of the 21 study patients (62%) had curve improvement or stabilization during the follow-up period. Eight of 21 patients (38%) had curve progression. Closer analysis reveals that the age, gender, and initial size of the scoliotic curve influenced the results of suboccipital decompression on the behavior of the scoliosis. Specifically, 10 of 11 patients (91%) who were less than 10 years of age at the time of suboccipital decompression have had their curves improve or stay the same during follow-up. In contrast, 5 of 7 female patients (72%) older than 10 years old with a curve greater than 40 degrees before suboccipital decompression have either been fused or are awaiting fusion.

Adolescent↗

Decompressive craniectomy for severe traumatic brain injury: Evaluation of the effects at one year.

OBJECTIVE: To assess the effect on outcome (1 yr) of decompressive craniectomy performed within or after the first 24 hrs post-trauma in severely head-injured trauma patients with intractable cerebral hypertension. DESIGN: Retrospective cohort study. SETTINGS: Intensive care unit of a university hospital. PATIENTS: Among 816 patients with severe head trauma (Glasgow Coma Scale < or =8), 40 underwent decompressive craniectomy. After data collection, patients were divided into two groups: early and late decompressive craniectomy. An early decompressive craniectomy was performed within the first 24 hrs in patients according to the following criteria: a Glasgow Coma Scale score <6 and the existence of clinical signs of cerebral herniation (absence of pupillary reflexes), correlated with abnormalities in computed tomography scan including hematoma, appearance of diffuse or unilateral brain swelling, and/or cerebral herniation. The intracranial pressure in these patients was not measured before the decompressive craniectomy was performed. A late decompressive craniectomy (>24 hrs) was performed according to following criteria: an intractable intracranial hypertension with intracranial pressure >35 mm Hg, a unilateral or bilateral absence of pupillary reflexes, and the same abnormalities in computed tomography scan as previously described. INTERVENTION: Twenty-seven patients with signs of cerebral herniation required the procedure at the time of initial evacuation of a mass lesion. In 13 patients, decompressive craniectomy was performed because of elevated intracranial pressure refractory to medical treatment consisting of cerebrospinal fluid derivation, deep sedation, osmotherapy, hyperventilation, and nesdonal or propofol. MEASUREMENTS AND MAIN RESULTS: Five patients (19%) in whom an early decompressive craniectomy was performed had good recoveries (social rehabilitation), eight patients (30%) remained in a persistent vegetative state or with a severe disability, and 14 died (52%). On the other hand, the performance of late decompressive craniectomy in case of medical treatment failure was followed by social rehabilitation in five patients (38%) and death in three patients (23%). A persistent vegetative state or a severe disability was observed in five patients (38%). Meningitis or cerebral abscess occurred in six patients after decompressive craniectomy and were easily cured by antibiotic treatment. CONCLUSIONS: In 40 patients with intractable intracranial hypertension and at very high risk of brain death, decompressive craniectomy allowed 25% of patients to attain social rehabilitation at 1 yr.

Adult↗

Gastrointestinal decompression after excision and anastomosis of lower digestive tract.

AIM: To discuss the clinical significance of postoperative gastrointestinal decompression in operation on lower digestive tract. METHODS: Three hundred and sixty-eight patients with excision and anastomosis of lower digestive tract were divided into two groups, i.e. the group with postoperative gastrointestinal decompression and the group without postoperative gastrointestinal decompression. Clinical therapeutic outcome and incidence of complication were compared between two groups. Furthermore, an investigation on application of gastrointestinal decompression was carried out among 200 general surgeons. RESULTS: The volume of gastric juice in decompression group was about 200 mL every day after operation. Both groups had a lower girth before operation than every day after operation. No difference in length of the first passage of gas by anus and defecation after operation was found between two groups. The overall incidence of complications was obviously higher in decompression group than in non-decompression group (28% vs 8.2%, P<0.001). The incidence of pharyngolaryngitis was up to 23.1%. There was also no difference between two groups regarding the length of hospitalization after operation. The majority (97.5%) of general surgeons held that gastrointestinal decompression should be placed till passage of gas by anus, and only 2.5% of surgeons thought that gastrointestinal decompression should be placed for 2-3 d before passage of gas by anus. Nobody (0%) deemed it unnecessary for placing gastrointestinal compression after operation. CONCLUSION: Application of gastrointestinal decompression after excision and anastomosis of lower digestive tract cannot effectively reduce gastrointestinal tract pressure and has no obvious effect on preventing postoperative complications. On the contrary, it may increase the incidence of pharyngolaryngitis and other complications. Therefore, it is more beneficial to the recovery of patients without undergoing gastrointestinal decompression.

Adult↗

Relationship between right-to-left shunts and cutaneous decompression illness.

The presence of a large right-to-left shunt is associated with neurological decompression illness after non-provocative dives, as a result of paradoxical gas embolism. A small number of observations suggest that cutaneous decompression illness is also associated with a right-to-left shunt, although an embolic aetiology of a diffuse rash is more difficult to explain. We performed a retrospective case--control comparison of the prevalence and sizes of right-to-left shunts determined by contrast echocardiography performed blind to history in 60 divers and one caisson worker with a history of cutaneous decompression illness, and 123 historical control divers. We found that 47 (77.0%) of the 61 cases with cutaneous decompression illness had a shunt, compared with 34 (27.6%) of 123 control divers (P<0.001). The size of the shunts in the divers with cutaneous decompression illness was significantly greater than in the controls. Thus 30 (49.2%) of the 61 cases with cutaneous decompression illness had a large shunt at rest, compared with six (4.9%) of the 123 controls (P<0.001). During closure procedures in 17 divers who had cutaneous decompression illness, the mean diameter of the foramen ovale was 10.9 mm. Cutaneous decompression illness occurred after dives that were provocative or deep in subjects without shunts, but after shallower and non-provocative dives in those with shunts. The latter individuals are at increased risk of neurological decompression illness. We conclude that cutaneous decompression illness has two pathophysiological mechanisms. It is usually associated with a large right-to-left shunt, when the mechanism is likely to be paradoxical gas embolism with peripheral amplification when bubble emboli invade tissues supersaturated with nitrogen. Cutaneous decompression illness can also occur in individuals without a shunt. In these subjects, the mechanism might be bubble emboli passing through an 'overloaded' lung filter or autochthonous bubble formation.

Case-Control Studies↗

Nitrogen partial pressures in man after decompression from simulated scuba dives at rest and during exercise.

In 5 subjects arterial and central venous nitrogen partial pressures (PN2) were measured after decompression from a chamber dive following a decompression schedule for scuba diving. The simulated dives consisted of exposure to air at 6 bar for 30 min corresponding to a depth of 50 m. Afterward the subjects were decompressed with decompression stops at 2.5, 2.2, 1.9, 1.6, and 1.3 bar with a total decompression time of 67 min. In 3 of the subjects the measurements were repeated after they had exercised (workload 75 W) during bottom time. Immediately after decompression and every 40 min until Minute 240 arterial and central venous blood samples were analyzed for PN2 using a manometric Van Slyke apparatus. Venous PN2 remained elevated until 160 min after decompression, indicating still incomplete nitrogen washout for at least 2 h after decompression had been accomplished. We did not find any difference in PN2 values after decompression from dives at rest and after exercise. Applying a computer program based on a wide range of theoretical tissue half-times nitrogen elimination proved to be consistent with Haldanian theories when using our decompression profile. Our data confirm that nitrogen elimination is prolonged after decompression from simulated dives at rest and after exercise.

Adult↗

Endoscopic decompression for acute colonic pseudo-obstruction.

BACKGROUND: Acute colonic pseudo-obstruction is often treated by colonoscopic decompression. Efficacy, safety, and outcome of endoscopic decompression was assessed. METHODS: Colonoscopic decompressions from 1988 to 1994 were reviewed. Resolution without further endoscopic intervention was defined as clinical success. RESULTS: Acute colonic pseudo-obstruction was diagnosed in 50 patients. Thirty-three cases followed surgery or trauma and 17 developed during severe medical illness. Orthopedic joint surgery was most common. Nineteen of 50 patients (38%) had severe underlying medical disease. Forty-one patients (82%) had one colonoscopic decompression with clinical success in 39 (95%). Nine patients (18%) required multiple (2 to 4) colonoscopic decompressions with clinical success in 5 (56%). A decompression tube positioned in the right colon (57%) and in the transverse colon (33%) had similar clinical success. In 8 procedures a decompression tube was not placed, with poor clinical success (25%). The overall clinical success of colonoscopic decompression was 88% (44 of 50). An endoscopic perforation occurred in 1 patient (2%). Overall hospital mortality was 30%. CONCLUSIONS: Colonoscopic decompression is effective and safe for acute colonic pseudo-obstruction that does not respond to conservative therapy. Most patients will respond to one colonoscopic decompression with decompression tube placement. Complete colonoscopy and cecal tube placement is unnecessary.

Acute Disease↗

Current trends in orbital decompression.

A questionnaire was sent to members of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) and the Orbital Society in regard to indications, surgical techniques and results of orbital decompression for Graves' disease. It was found that more than 60% of orbital decompressions were performed for mild to severe exophthalmos to correct corneal exposure or disfigurement. A total of 3.9% of these procedures were performed to relieve visual loss in compressive neuropathy. The large majority of decompressions were performed using antral-ethmoidal decompression via a translid or fornix approach. The amount of retrodisplacement was greatest with Kennerdell-Maroon or four-wall decompression and the least with lateral wall decompression. The antral-ethmoidal and three-wall decompression techniques gave an average of 4 to 6 mm of retrodisplacement. It was determined from the survey that antral-ethmoidal decompressions performed through the transantral approach were more likely to relieve the pressure in compressive neuropathy and also more likely to induce a worsening of muscle balance. In contrast, antral-ethmoidal decompressions performed via the translid approach were not as effective in relieving compressive neuropathy but had a much lower incidence of worsened muscle balance, and in fact, resulted in a higher incidence of improved muscle balance. The same trends were confirmed in the author's surgical practice, and an anatomic explanation is offered. The importance of creating nasoantral windows following decompression is emphasized. The risks of cerebrospinal fluid leakage and changes in eyelid positioning following decompression are described.

Combined Modality Therapy↗

Transforaminal and posterior decompressions of the lumbar spine. A comparative study of stability and intervertebral foramen area.

STUDY DESIGN: Ten fresh, cadaveric, two-vertebrae, functional spinal units were used to study the pathoanatomy, intervertebral foraminal area, and flexibility changes after posterior and transforaminal decompression. OBJECTIVES: To determine the feasibility of an endoscopic transforaminal approach as an alternative to conventional approaches, to establish the adequacy of transforaminal decompression without destabilizing the spine, and to study the structural changes in the spine after decompressions. SUMMARY OF THE BACKGROUND DATA: Posterior decompression entails major dissection and excision of bone and ligaments to access the spinal canal. Posterior decompression may be complicated by acute or chronic spinal instability, and the adequacy of lateral decompression is highly subjective. METHODS: The functional spinal units were mounted in quick-setting epoxy blocks. Pre- and postoperative computed tomography scans were taken to study changes in the foraminal area. Pre- and postoperative flexibility and anatomic studies were performed to compare the results. RESULTS: A 45.5% increase in the intervertebral foraminal area was possible, there was no flexibility change, and minimal anatomic damage to the spine was noted after transforaminal decompression. A 34.2% increase in the intervertebral foraminal area and a significant increase in extension and axial rotation flexibility were noted after the posterior decompression. CONCLUSION: Transforaminal decompression produced a significantly larger increase in the intervertebral foraminal area than posterior decompression, without increasing the range of motion or neutral zone in any direction. Because there was no violation of the anatomic integrity of the spine in the transforaminal approach, the risk of surgically induced instability was minimized. Endoscopic transforaminal decompression is a feasible alternative to current approaches.

Adult↗

Exercise effects during diving and decompression on postdive venous gas emboli.

BACKGROUND: Exercise and diving have generally been associated with an increased risk of decompression sickness (DCS), thus accounting for the lack of studies involving exercise during decompression. However, theoretical and observational evidence contrary to this association motivated the present investigation on the effects of moderate, intermittent exercise during diving and/or during decompression on venous gas emboli (VGE) activity following a dive. HYPOTHESIS: VGE observed at both the precordium and subclavian vein sites after diving should be reduced if moderate exercise is performed during decompression vs. remaining inactive. METHODS: In a water-filled hyperbaric chamber, 39 healthy male subjects were compressed to a pressure of 450 kPa (45 msw) for 30 min followed by 55 min of staged decompression. Subjects were either active or inactive at the bottom phase (450 kPa) and/or during the decompression. Activity comprised three 5-min intervals of moderate arm or leg exercise at the bottom and five such intervals during decompression. After decompression, VGE were monitored at the precordium and subclavian vein sites using Doppler detection. Bubble activity scores were converted to various indices and analyzed using non-parametric statistics. RESULTS: VGE activity was invariant as to whether subjects were active or sedentary during the bottom phase of the dive. However, it was significantly lower for all indices examined (p < 0.05) after dives in which exercise was performed during decompression vs. inactive decompression. CONCLUSION: Moderate, intermittent physical activity during decompression decreases VGE activity after diving.

Adult↗