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PubMed1999

Spinous process osteotomies to facilitate lumbar decompressive surgery.

STUDY DESIGN: A technique for lumbar decompression using spinous process osteotomies is described, and the outcomes are studied prospectively. OBJECTIVE: To describe a technique that affords a wide exposure for decompression while minimizing damage to surrounding tissues, and to analyze the outcomes formally using the technique. SUMMARY OF BACKGROUND DATA: Commonly used techniques of lumbar decompression, which include bilateral takedown of paraspinal musculature and aggressive bony resection, can result in significant iatrogenic sequelae, whereas minimally invasive techniques often provide inadequate visualization and/or decompression. METHOD: Unilateral limited takedown of the multifidus is undertaken, followed by spinous process osteotomies at the involved levels. The spinous processes with the attached interspinous/supraspinous ligaments are then retracted. A complete "trumpeted" decompression is then undertaken. Fifty consecutive patients undergoing the procedure were analyzed prospectively and at follow-up by an independent observer using a validated functional outcome measure, a visual analog pain scale, and a patient satisfaction score. RESULTS: Functional outcome scores improved on average by 47%, pain levels were reduced by 66%, and high satisfaction rates were reported by 83% of patients. CONCLUSIONS: The technique affords excellent visualization and a wide area available for Kerrison use and angulation while minimizing destruction to tissues not directly involved in the pathologic process, including the paraspinal musculature as well as the interspinous/supraspinous ligament complex and facets. Additionally, it minimizes dead space and improves the cosmetic result.

Aged↗
PubMed1999

Radiologic and computed tomography image evaluation of bone regrowth after wide surgical decompression for lumbar stenosis.

STUDY DESIGN: Retrospective study of bone regrowth after decompressive surgery for lumbar spinal stenosis. OBJECTIVES: To assess bone regrowth at the operation site, to compare the bone regrowth rate calculated from plain radiographs with computed tomographic image examinations, to determine the effects of bone regrowth on clinical outcome, and to investigate the factors promoting bone regrowth. SUMMARY OF THE BACKGROUND DATA: Moderate or marked bone regrowth in a surgical defect has been reported in most patients after decompression for lumbar spinal stenosis. Postoperative bone regrowth is related to recurrence of neurologic symptoms in the middle of and later on in follow-up periods. METHODS: Twenty-three patients who underwent decompressive surgery for lumbar spinal stenosis, with an average follow-up of 8 years, were evaluated retrospectively regarding the degree of bone regrowth at the posterior arch. Early postoperative radiographs and computed tomographic images were compared with those obtained at final follow-up. Bone regrowth at the operation sites was evaluated as a regrowth percentage of the original laminectomy site. RESULTS: Decompressive surgery caused bone regrowth to occur at the operation site in most of the patients. However, this regrowth was mild because the mean bone regrowth rate evaluated from plain radiographs averaged 11% and from computed tomographic images 7.7%. In only 20% of the patients was the bone regrowth rate more than 20%. Changes were found to be more elevated at the facet joint level than at the pedicle level. Evaluations of regrowth obtained from plain films and computed tomographic image examinations were compared. Radiographs seemed to overestimate the bone regrowth. The association of postoperative spinal instability with the development of new bone was statistically significant. No relation between bone regrowth and clinical outcome was found. CONCLUSIONS: Bone regrowth in a surgical defect occurs in most patients after posterior decompression. In this study the bone regrowth rate was mild and did not affect the clinical outcome.

Adult↗
PubMed2000

Minimum 10-year outcome of decompressive laminectomy for degenerative lumbar spinal stenosis.

STUDY DESIGN: A retrospective follow-up study was conducted in patients who underwent decompressive laminectomy for degenerative lumbar spinal stenosis. OBJECTIVES: To describe the long-term outcome of decompressive laminectomy performed for degenerative lumbar spinal stenosis, and to investigate preoperative factors that influenced outcomes, especially risk factors predisposing patients to poor results. SUMMARY OF BACKGROUND DATA: The success rate of surgical treatment of decompressive laminectomy for lumbar spinal stenosis varies. Long-term follow-up investigations have indicated deterioration of outcome; however, the causes of deterioration have not been fully investigated, and there have been no reports with a minimum 10-year follow-up. METHODS: Of 151 patients who underwent decompressive laminectomy from 1980 through 1989, 37 were followed up for a minimum of 10 years. The mean age at surgery was 60.9 +/- 8. 2 years (range, 43-76), and the average follow-up period was 13.1 +/- 2.1 years (range, 10.1-17.4). The results were evaluated by the criteria of the Japanese Orthopedic Association Lumbar Score, and the outcome was classified as excellent at more than 75% improved score; good, 50-75%; fair, 25-49%; and poor, 0-24% or less. Information about impairment of activities of daily living was also obtained at follow-up. Associations between preoperative clinical and radiographic variables and clinical outcome were evaluated statistically. RESULTS: In all patients, the average score improvement of 55.2 +/- 31.6% was regarded as acceptable. The postoperative score and percentage of improvement of low back pain were lower than those of leg pain and walking ability. No impairment in activities of daily living was found in 62.2% of the patients. Rate of improvement was evaluated as excellent in 13 (35.1%), good in 8 (21.6%), fair in 8, and poor in 8 patients. Three patients required additional surgery because of disc herniation at the laminectomied segments. The patients with multiple laminectomy (P = 0.034) and more than 10 degrees preoperative sagittal rotation angle (P = 0.018) showed a significantly poorer outcome than the remainder of the patients. CONCLUSIONS: Long-term follow-up showed that even without spinal fusion, more than half the patients were evaluated as excellent or good. Patients with more than a 10 degrees sagittalrotation angle who need multiple laminectomy, should be given information about the possibility of earlier deterioration of the outcome, and alternative or additional treatment such as concomitant spinal fusion with decompression may be considered.

Activities of Daily Living↗
PubMed2002

Factors predicting hospital stay, operative time, blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation.

STUDY DESIGN: A retrospective chart review was conducted for 112 patients who underwent revision posterior lumbar spine decompression, fusion, and segmental instrumentation. OBJECTIVE: To ascertain factors predicting hospital stay, operative time, blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation. SUMMARY OF BACKGROUND DATA: Posterior lumbar spine decompression and fusion with segmental instrumentation is a common procedure in the treatment of degenerative lumbar spine disorders. Many patients undergoing this procedure have had previous lumbar spine surgery, yet little is known about the factors predicting hospital stay, operative time, blood loss, and transfusion. METHODS: The charts of 112 patients (53 men and 59 women) with degenerative lumbar spinal stenosis who underwent revision surgery from March 1992 to June 1999 were reviewed. Their average age was 54 years (range, 27-84 years). All the surgeries included decompression and fusion with segmental instrumentation. The patients' demographics, comorbid conditions, factors related to previous lumbar spine surgery, diagnosis, number of levels fused, and preoperative hemoglobin and hematocrit were collected and used as the independent variables. Multiple regression analysis was used to ascertain factors predicting length of hospital stay, operative time, intraoperative blood loss, and transfusion. RESULTS: The mean length of hospital stay was 6 +/- 2.4 days, the operative time 280 +/- 62 minutes, the estimated intraoperative blood loss 1073 +/- 716 mL, and the total volume of blood transfused 1.04 +/- 1.17 U. For 63% of the patients, a blood transfusion was needed. Increasing age was the significant predictor for hospital stay (P < 0.001). The factors predicting operative time were number of levels fused (P < 0.001), diagnosis of degenerative scoliosis (P < 0.05), and excessive body weight (P < 0.01). The factors predicting intraoperative blood loss were number of levels fused (P < 0.01), body weight (P < 0.001), and high preoperative hemoglobin (P < 0.001). Both logistic and linear regression analysis showed that the factors predicting blood transfusion were number of levels fused (P < 0.01), age (P < 0.05), and low preoperative hemoglobin (P < 0.001). Other factors associated with hospital stay and blood transfusion were unemployment associated with three or more comorbid conditions and complications. The women had less intraoperative blood loss (P < 0.01), but received more transfused blood than the men (P < 0.01). CONCLUSIONS: Number of levels fused and age seem to be the most significant factors predicting hospital stay, operative time, intraoperative blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation.

Adult↗
PubMed2002

Transpedicular decompression and pedicle subtraction osteotomy (eggshell procedure): a retrospective review of 59 patients.

STUDY DESIGN: Outcomes of transpedicular decompression and/or osteotomy were analyzed retrospectively. OBJECTIVES: To determine the effectiveness of decompression and correction, fusion stability, procedural safety, neurologic outcome, complication rates, and overall patient outcomes. SUMMARY OF BACKGROUND INFORMATION: The "eggshell" procedure is reserved for complex reconstructive problems in the treatment of acute trauma, deformity, tumor, or infection. The technique encompasses a range of procedures from simple transpedicular decompression and posterior fusion to more complex procedures, including transpedicular vertebrectomy and strut-grafting or pedicle subtraction (closing wedge) osteotomy with posterolateral fusion. These procedures are completed through a single posterior midline incision, with anterior spinal canal decompression a transpedicular approach, accompanied by a posterior or posterolateral fusion and internal fixation. METHODS: From 1990 to 1998, 59 "eggshell" procedures were performed for 37 deformity cases and 22 tumor or infection cases. Forty-two patients had a minimum 2-year follow-up, averaging 4.5 +/- 2.5 years. Thirty-six patients were available for patient interview, physical examination, and radiographic analysis. Outcome data were collected using SF-36 and SRS instruments. RESULTS: No patients worsened neurologically, and all incomplete spinal cord injuries improved. All patients achieved solid fusion radiographically. Correction with osteotomy averaged 26 degrees. Systemic complication rates were low with a pulmonary complication rate of 5%. Blood loss averaged 2342 mL. Overall patient outcomes were below population norms, but patient satisfaction was very high. CONCLUSION: Overall, the results suggest that the "eggshell" procedure is a reliable and safe technique to achieve anterior decompression of the spinal canal and posterior stabilization through a single approach.

Adolescent↗
PubMed2002

Orbital decompression: current concepts.

The orbit in Graves disease undergoes expansion in soft tissue content as a result of the infiltration of orbital fat, extraocular muscles, and the lacrimal gland. Compression of the intraorbital contents leads to disorders of the lid-corneal interface, keratopathy, motility disturbances, exophthalmos, and optic neuropathy. Orbital decompression has traditionally been reserved for those patients with unremitting optic neuropathy. This article provides a historical review of orbital decompression, as well as a review of the evolution of surgical approaches toward both soft tissue and bony decompression. Recent trends in surgical management include fat decompression, more extensive posterior sculpting of the lateral wall, and direct approaches to the medial wall. Preoperative predictors of diplopia and hypoglobus are addressed, as are the various techniques that are employed to limit new postoperative strabismus. The roles of endoscopy and combined surgical techniques are also reviewed. Expanded indications for decompression and its effect on increased intraocular pressure are discussed as well.

Decompression, Surgical↗
PubMedDate not supplied

Studies on the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia.

OBJECTIVE: To evaluate the operative outcomes and mechanisms of microvascular decompression in treating typical and atypical trigeminal neuralgia. METHODS: A group of 45 patients with typical trigeminal neuralgia and 17 patients with atypical trigeminal neuralgia treated by micro-vascular decompression from 2000 to 2002 were reviewed, including their clinical presentations, operative findings, and outcomes. RESULTS: Of 45 patients with typical trigeminal neuralgia, the mean duration was 3.1 years, and the mean age of pain onset was 60.3 years. Single trigeminal division was involved in 20 patients (44.4%), and 2 or 3 divisions were involved in the other 25 patients (55.6%). During the operation, artery compression was found in 39 patients (86.7%), and the combined artery and venous compression was found in 6 patients (13.3%). Postoperatively, complete pain relief was achieved in 44 patients (97.8%), and significant pain relief was achieved in 1 patient (2.2%). As for 17 patients with atypical trigeminal neuralgia, the mean duration and the mean age of pain onset was 8.7 years and 55.5 years, respectively. Two or 3 trigeminal divisions were involved in all of these patients. During operation, artery compression occurred in 10 patients (58.8%), and the combined artery and venous compression was found in 7 patients (41.2%). Postoperatively, complete pain relief was achieved in 5 patients (29.4%), and partial pain relief was achieved in 10 patients (58.8%), and 2 patients showed no response to microvascular decompression. CONCLUSIONS: The operative outcome of microvascular decompression in patients with typical trigeminal neuralgia was better than that of patients with atypical trigeminal neuralgia, which perhaps related to short duration, late onset of pain, limited distribution, artery compression, and complete operative decompression.

Adult↗
PubMed2003

Osteonecrosis after powered core decompression.

A 44-year-old man with alcohol-related osteonecrosis of his left femoral head, Ficat Stage 2, was treated by femoral head decompression. During this procedure the (1/4)-inch trephine driven by a power reamer became lodged in the femoral head and became hot to the touch. The trephine eventually was removed with difficulty after the decompression was completed. Four and a half years later, the patient continued to have progressive pain and difficulty ambulating. A radiograph at the time revealed a wide zone of symmetric increased density about the core decompression track. A total hip arthroplasty was done, yielding the femoral head and neck for study. Histologic sections of the femoral head and neck showed that the entire length of the core decompression track in the specimen was surrounded by 2.7 cm of unrepaired necrotic bone. The evidence suggests that extensive additional necrosis was produced iatrogenically during the core decompression with the powered trephine. Necrosis secondary to either heat generation or increased pressure along the trephine track is presented as possible mechanisms for this unusual finding.

Adult↗
PubMed2006

Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis.

STUDY DESIGN: Prospective clinical study. OBJECTIVE: To test whether elastic stabilization with the Dynesys system (Zimmer Spine, Minneapolis, MN) provides enough stability to prevent further progression of spondylolisthesis as well as instability after decompression for spinal stenosis with degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: In spinal stenosis with degenerative spondylolisthesis, decompression and fusion is widely recommended. However, patients have donor site pain. In 1994, a dynamic transpedicular system (Dynesys) was introduced to the market, stating that stabilization is possible without bone grafting. METHODS: A total of 26 patients (mean age 71 years) with lumbar spinal stenosis and degenerative spondylolisthesis underwent interlaminar decompression and dynamic stabilization with the Dynesys system. Minimum follow-up was 2 years. Operative data, clinical outcome, and plain and flexion/extension radiographs were obtained and compared to preoperative and postoperative data. RESULTS: Mean leg pain decreased significantly (P < 0.01), and mean walking distance improved significantly to more than 1000 m (P < 0.01). There were 5 patients (21%) who still had some claudication. A total of 21 patients (87.5%) would undergo the same procedure again. Radiographically, no significant progression of spondylolisthesis could be detected. The implant failure rate was 17%, and none of them were clinically symptomatic. CONCLUSIONS: In elderly patients with spinal stenosis with degenerative spondylolisthesis, dynamic stabilization with the Dynesys system in addition to decompression leads to similar clinical results as seen in established protocols using decompression and fusion with pedicle screws. It maintains enough stability to prevent further progression of spondylolisthesis or instability. With the Dynesys system, no bone grafting is necessary, therefore, donor site morbidity can be avoided.

Aged↗
PubMed2007

Risk factors for the development of perioperative complications in elderly patients undergoing lumbar decompression and arthrodesis for spinal stenosis: an analysis of 166 patients.

STUDY DESIGN: Retrospective review. OBJECTIVE: To quantify and describe perioperative complication rates in a large series of well-matched elderly patients who underwent lumbar decompression and arthrodesis. SUMMARY OF BACKGROUND DATA: Posterior lumbar decompression and fusion is frequently performed to treat lumbar stenosis with instability. An increasing number of elderly patients are undergoing operative treatment for degenerative lumbar disease. The reported morbidity of performing decompression and arthrodesis in this population varies widely in the literature, with recent reports showing a high rate of major complications. METHODS: A total of 166 patients age 65 or older that underwent primary posterior lumbar decompression and fusion with (group 1; n = 75) or without (group 2; n = 91) instrumentation were included. Hospital records were reviewed for the occurrence of any complications (major and minor), the need for transfusion, estimated length of stay, and disposition at discharge. Logistic regression (with the presence/absence of major complications as the dependent variable) was used to identify risk factors for the occurrence of a complication. RESULTS: Five major complications (3%) occurred (group 1, 1; group 2, 4). Minor complications developed in 30.7% of group 1 and 31.9% of group 2. There were no deaths, and only one perioperative complication was attributable to the use of instrumentation. Decompression/fusion of 4 or more segments was significantly associated with the occurrence of a major complication. Advanced age, the presence of medical comorbidities, or the use of instrumentation did not increase the rate of major or minor complications. The occurrence of either a major or minor complication prolonged hospital stay. CONCLUSIONS: Posterior lumbar decompression and fusion can be safely performed in elderly patients, with a low rate of major complications. The addition of instrumentation does not increase the complication rate. These results differ from those previously reported in the literature, which describe a significantly higher rate of complications in this age group, with a prolonged rate of hospitalization.

Aged↗
PubMed2004

Long-term physical, mental, and functional consequences of abdominal decompression.

BACKGROUND: The long-term physical, mental, and functional consequences of abdominal decompression for intra-abdominal hypertension are unknown. METHODS: Thirty patients in various stages of abdominal decompression and delayed fascial closure for massive incisional hernia completed the SF-36 Health Survey and answered questions regarding their employment and pregnancy status. RESULTS: Patients awaiting abdominal wall reconstruction demonstrated significantly decreased perceptions of physical, social, and emotional health (p < 0.05), whereas patients who had completed definitive fascial closure demonstrated physical and mental health scores equivalent to the U.S. general population. Ultimately, 78% of patients employed before decompression returned to work. CONCLUSION: Abdominal decompression with skin grafting and delayed fascial closure initially decreases patient perception of physical, social, and emotional health, but subsequent abdominal wall reconstruction restores physical and mental health to that of the U.S. general population. Abdominal decompression does not prevent return to gainful employment and should not be considered a permanently disabling condition.

APACHE↗
PubMed2006

Cerebrospinal fluid drainage and cranial decompression prolong survival in rats with fulminant hepatic failure.

Fulminant hepatic failure (FHF) is a devastating disease. Liver transplantation is the definitive treatment. However, a third of these patients die due to brain edema before a donor becomes available. Cerebrospinal fluid (CSF) drainage and decompressive craniectomy have been used to treat brain edema in brain trauma and hemispheric stroke. However, their role in brain edema associated with FHF has not been examined. In this study we evaluated the potential effects of CSF drainage and decompressive craniectomy on survival in FHF using an experimental model in rats. In CSF drainage experiments all animals had ventriculostomy placed. Five days later FHF was induced with d-galactosamine. Those FHF rats that progressed into comatose stages either received CSF aspiration or did not. In separate experiments the study rats had either a decompressive craniectomy or a sham procedure. FHF was induced 5 days later. We found that both CSF drainage and decompressive craniectomy significantly increased survival of FHF rats compared with the controls: 53.2 +/- 1.1 vs. 48.7 +/- 1.5 h (P = 0.031), and 69.4 +/- 3.9 vs. 53.7 +/- 3.2 h (P = 0.009), respectively. In conclusion, these findings suggest that CSF drainage and decompressive craniectomy may increase the window of opportunity for liver transplantation.

Animals↗
PubMed1997

Orbital decompression for thyroid orbitopathy.

BACKGROUND: Severe thyroid orbitopathy may result in optic neuropathy, corneal exposure and disfiguring proptosis. Orbital decompression has most commonly been performed for optic neuropathy, but with improved techniques, more patients are undergoing decompression for other indications. PURPOSE: This report evaluates the results and morbidity of orbital decompression for thyroid orbitopathy performed by one surgeon. METHODS: The records of 33 patients (53 orbits) undergoing orbital decompression for thyroid orbitopathy were analysed for changes in visual acuity and colour vision (where the indication was optic neuropathy) and reduction in proptosis. Complications were also analysed. RESULTS: Visual acuity and colour vision improved in all 33 eyes with optic neuropathy in the short term postoperative period (4 weeks), but later deteriorated in five eyes (6.6%) of 4 patients (19%). Proptosis decreased by a mean 5.3 mm (range, 1-10). Diplopia developed or worsened overall in 10 of 33 patients (30%), but only in one of 12 (8%) where the indication was cosmesis or corneal exposure. Diplopia improved in 2 of 33 (6%). All patients with symptomatic diplopia achieved binocular single vision in a useful range after one and sometimes two squint procedures. No patient lost vision as a result of surgery. CONCLUSIONS: Orbital decompression is effective in improving vision in most patients with thyroid optic neuropathy, but induces or worsens diplopia in a high proportion of these patients. Proptosis can be effectively and dramatically improved.

Adult↗
PubMed1998

Decompression sickness risk in rats by microbial removal of dissolved gas.

We present a method for reducing the risk of decompression sickness (DCS) in rats exposed to high pressures of H2. Suspensions of the human colonic microbe Methanobrevibacter smithii were introduced via a colonic cannula into the large intestines of the rats. While the rats breathed H2 in a hyperbaric chamber, the microbe metabolized some of the H2 diffusing into the intestine, converting H2 and CO2 to methane and water. Rate of release of methane from the rats, which was monitored by gas chromatography, varied with chamber H2 pressure. This rate was higher during decompression than during compression, suggesting that during decompression the microbe was metabolizing H2 stored in the rats' tissues. Rats treated with M. smithii had a 25% (5 of 20) incidence of DCS, which was significantly lower (P < 0.01) than the 56% (28 of 50) incidence of untreated controls, brought on by a standardized compression and decompression sequence. Thus using a microbe in the intestine to remove an estimated 5% of the body burden of H2 reduced DCS risk by more than one-half. This method of biochemical decompression may potentially facilitate human diving.

Animals↗
PubMed1987

Role of oxygen in the production of human decompression sickness.

In the calculation of decompression schedules, it is commonly assumed that only the inert gas needs to be considered; all inspired O2 is ignored. Animal experiments have shown that high O2 can increase risk of serious decompression sickness (DCS). A trial was performed to assess the relative risks of O2 and N2 in human no-decompression dives. Controlled dives (477) of 30- to 240-min duration were performed with subjects breathing mixtures with low (0.21-0.38 ATA) or high (1.0-1.5 ATA) Po2. Depths were chosen by a sequential dose-response format. Only 11 cases of DCS and 18 cases of marginal symptoms were recorded despite exceeding the presently accepted no-decompression limits by greater than 20%. Analysis by maximum likelihood showed a shallow dose-response curve for increasing depth. O2 was estimated to have zero influence on DCS risk, although data variability still allows a slight chance that O2 could be 40% as effective as N2 in producing a risk of DCS. Consideration of only inert gases is thus justified in calculating human decompression tables.

Decompression Sickness↗
PubMed1998

Probabilistic models of the role of oxygen in human decompression sickness.

Probabilistic models of human decompression sickness (DCS) have been successful in describing DCS risk observed across a wide variety of N2-O2 dives but have failed to account for the observed DCS incidence in dives with high PO2 during decompression. Our most successful previous model, calibrated with 3,322 N2-O2 dives, predicts only 40% of the observed incidence in dives with 100% O2 breathing during decompression. We added 1,013 O2 decompression dives to the calibration data. Fitting the prior model to this expanded data set resulted in only a modest improvement in DCS prediction of O2 data. Therefore, two O2-specific modifications were proposed: PO2-based alteration of inert gas kinetics (model 1) and PO2 contribution to total inert gas (model 2). Both modifications statistically significantly improved the fit, and each predicts 90% of the observed DCS incidence in O2 dives. The success of models 1 and 2 in improving prediction of DCS occurrence suggests that elevated PO2 levels contribute to DCS risk, although less than the equivalent amount of N2. Both models allow rational optimization of O2 use in accelerating decompression procedures.

Air Pressure↗
PubMed2006

Decompression sickness in the rat following a dive on trimix: recompression therapy with oxygen vs. heliox and oxygen.

Trimix (a mixture of helium, nitrogen, and oxygen) has been used in deep diving to reduce the risk of high-pressure nervous syndrome during compression and the time required for decompression at the end of the dive. There is no specific recompression treatment for decompression sickness (DCS) resulting from trimix diving. Our purpose was to validate a rat model of DCS on decompression from a trimix dive and to compare recompression treatment with oxygen and heliox (helium-oxygen). Rats were exposed to trimix in a hyperbaric chamber and tested for DCS while walking in a rotating wheel. We first established the experimental model, and then studied the effect of hyperbaric treatment on DCS: either hyperbaric oxygen (HBO) (1 h, 280 kPa oxygen) or heliox-HBO (0.5 h, 405 kPa heliox 50%-50% followed by 0.5 h, 280 kPa oxygen). Exposure to trimix was conducted at 1,110 kPa for 30 min, with a decompression rate of 100 kPa/min. Death and most DCS symptoms occurred during the 30-min period of walking. In contrast to humans, no permanent disability was found in the rats. Rats with a body mass of 100-150 g suffered no DCS. The risk of DCS in rats weighing 200-350 g increased linearly with body mass. Twenty-four hours after decompression, death rate was 40% in the control animals and zero in those treated immediately with HBO. When treatment was delayed by 5 min, death rate was 25 and 20% with HBO and heliox, respectively.

Animals↗
PubMed2000

Complete visual recovery in osteopetrosis by early optic nerve decompression.

Visual loss with optic atrophy is common in osteopetrosis. The efficacy of optic nerve decompression in patients with osteopetrosis is still controversial. The purpose of this study is to report that visual deterioration in osteopetrosis can be completely reversed by early optic nerve decompression. An 8-year-old female patient with osteopetrosis was found to have reduced visual acuity on routine ophthalmologic examination. Extensive optic nerve decompression was performed. It not only included unroofing the optic canal, but also drilling away bone on both sidewalls of the optic nerve. Both optic nerves were decompressed during the same surgical procedure. Progressive loss of vision associated with osteopetrosis can be prevented by optic nerve decompression in the early stage of visual deterioration. When managing patients with osteopetrosis, the importance of careful and regular assessment of visual function should be stressed.

Child↗