Wall Decompression Research Articles

Active compression-decompression CPR: a progress report

Within the last several years a new method of CPR, termed active compression-decompression (ACD) CPR was developed. Based upon the theory that active rather than passive chest wall decompression would augment venous return and ventilation by causing an increase in negative intrathoracic pressure during the decompression phase of CPR, a hand-held device was designed and is now being used clinically. Studies in dogs and pigs in ventricular fibrillation have demonstrated a significant improvement in systolic blood pressure, coronary perfusion pressure and total brain and myocardial blood flow with ACD CPR compared with standard CPR. Animal and human studies suggest that the mechanism of ACD CPR is complex, with coronary perfusion occurring during both the compression and decompression phases. Clinical studies comparing ACD to standard CPR in patients in cardiac arrest demonstrate that immediate resuscitation rates are nearly doubled when ACD CPR is started within 10 min after cardiac arrest. The potential long term benefits of ACD CPR remain under investigation.

Treatment Of Exophthalmos By Orbital Fat Removal

Decompression of the orbit by removal of fat is a safe method to obtain functional and aesthetic improvement in exophthalmos disease. In comparison with traditional orbital wall decompression, the complication rate is low.

Mechanisms of Visual Loss in Severe Proptosis

Vision loss in orbital hypertension secondary to sudden space-occupying lesions is usually attributed to one of three causes: central retinal artery occlusion, direct compressive optic neuropathy, or compression of optic nerve vasculature. Accepted modes of decompressive therapy include lateral canthotomy and cantholysis; drainage of localized orbital air, hematoma, or abscess; and bony wall decompression. Five cases are presented in which orbital hypertension caused severe proptosis with traction on the optic nerve and tenting of the posterior globe. Another mechanism contributing to visual loss is proposed in these cases: ischemic optic neuropathy due to stretching of nutrient vessels. In these cases, rapid posterior decompression should theoretically be favored to reduce orbital pressure and relieve traction on the optic nerve vasculature.

Medial and Lateral Wall Decompression for Thyroid Ophthalmopathy. C. Leone, K. Piest, and R. Newman. Am J Ophthalmol 1989;108

Medial and Lateral Wall Decompression for Thyroid Ophthalmopathy. C. Leone, K. Piest, and R. Newman. Am J Ophthalmol 1989;108

Endoscopic Transnasal Orbital Decompression

Orbital decompression for dysthyroid orbitopathy has traditionally been performed through either an external or a transantral approach. The advent of intranasal endoscopes allowed for the development of a transnasal approach for medial and inferior orbital wall decompression. Using this approach, orbital decompressions were performed on 13 orbits in eight patients with severe complicated dysthyroid orbitopathy. Simultaneous bilateral lateral orbitotomies were performed on five patients. Walsh-Ogura decompressions and lateral orbitotomies were performed on two orbits. When combined with lateral orbitotomy, Hertel measurements improved an average of 5.7 mm in orbits decompressed transnasally and 4.5 mm in orbits decompressed with a Walsh-Ogura approach. Transnasal decompression alone improved Hertel measurements an average of 4.7 mm. Visual acuity improved in three of four patients with optic neuropathy, and in all patients with exposure keratopathy. We conclude that the endoscopic transnasal approach provides comparable decompression to traditional methods while avoiding the morbidity of an external ethmoidectomy or Caldwell-Luc antrotomy.

Medial and Lateral Wall Decompression for Thyroid Ophthalmopathy

A two-wall decompression of the orbit, consisting of removal of the medial and lateral walls, was successful in eight patients with thyroid ophthalmopathy. The lateral wall was by removed by using the standard orbitotomy technique in addition to enlarging the space with a pneumatic burr, and the medial wall was removed through a direct medial canthal incision. Two patients had optic neuropathy, one had intermittent subluxation of the globe, and five had symptoms of exposure or increased pressure in the orbital area. In our eight patients, the two with optic neuropathy improved, the patient with subluxation of the globe became asymptomatic, and the other five had less exposure and were more comfortable. The amount of decompression ranged between 4 and 7 mm. The lacrimal sac was injured in one patient; temporary silicone intubation avoided any permanent sequela.

Pressure-volume orbital measurement comparing decompression approaches.

Commonly used orbital decompressions are lateral wall, antral-ethmoidal, "three-wall," and "four-wall" decompressions. Bladders filled with saline were placed in intact bony orbits before and after decompression for comparison of compliance curves by these four methods. The lateral wall decompressions produced the least volume change, while the four-wall produced the most. The three-wall decompression provided next best pressure reduction.

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, antralethmoidal 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.

Pressure-synchronized cineangiography during experimental cardiopulmonary resuscitation.

Pressure-synchronized cineangiography during experimental cardiopulmonary resuscitation.

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.