D.C.S. violation consequence

Osseo-necrosis of the Divers
(Aseptic Necrosis of the bone in Divers and Scuba Divers)
Collaboration of Dr. Eric Salado and Ricardo G. Hernandez
(Senior Instructor SAFER)

“It’s one of the dire consequences of the disease by decompression diving” It must be said that even though there are other causes for this disease, in this article we will confine ourselves to what concerns its direct relationship with the autonomous diving on compressed or enriched air. But, more particularly, we aim to draw the attention of practitioners of diving with open systems self-contained compressed air (SCUBA) that while using this diving method practice hunting underwater, although this condition can occur in various circumstances.

Origins of decompression sickness

In the nineteenth century during construction of the bridge from Brooklyn into New York, workers were used very large metal tubes, called “caissons” for the underwater work of building the pillars of the bridge. Large numbers of workers were reported with symptoms of decompression sickness, then little known. Mr. Washington Roebling director of the works, oversaw the labor of the workers and visited frequently those cylinders, which were repeatedly subjected to conditions of high ambient-air pressure, and consequently he acquired in this way “ Caissons Disease”” he became so grievously impaired that he had to run the final part of the construction of the bridge from the window of his house near the bay, as he became a paraplegic confined to a wheelchair for the rest of his life.

Among other consequences, one of the manifestations of the decompression disease is what’s denominated vascular necrosis Disbaric Osteonecrosis, or Ischemic Osteonecrosis or plainly; bone death. (Greek “baros” pressure or weight) by exposure to high pressure breathing gases while in immersion underwater.

The origin of the term comes from necrosis Greek word “nécros” which means corpse, death or decay. The term aseptic implies the absence of infection.

Causes and risk factors

The Disbaric Osteonecrosis or aseptic bone necrosis is a rare condition that can happen to all sorts of divers or divers using S.C.U.B.A. during sports and recreational although it is much more common in professional divers for their lengthy and repetitive periods of immersion underwater breathing air or another gas mixture at high pressure.

The main cause of this condition is diving without a strict respect for decompression tables either by ignorance or negligence.

Note: The decompression tables establish a time-scale depth limiting the stay or indicating a rise much more slowly with some stops before coming to the surface to allow time to gas dissolved in the blood to gasify again in the lungs and be expelled to the outside world through breathing.

During diving, gases are compressed by the effect of high pressure into liquid state and pass into the bloodstream (Henry’s Law) when emerging from the depths these gases need some time to regain its gaseous state in the lungs through pulmonary blood circulation. The violation of these tables, the surfacing of the diver faster than what was established by the tables or dive computer, or not stopping at the pre-set depth as set forth in that particular case can cause the formation of nitrogen bubbles that act as obstructions inside the blood vessels blockading the flow. These “micro” blood clot caused by avascular necrosis can eventually lead to the death of bone tissue. The classic graphic demonstration is the quickly removal of a bottle of soda water cap resulting in an excessive bubbling as fluid’s pressure drops and violently release gases which were previously dissolved and unseen in the liquid.

It occurs more frequently at the ends of bones of large joints such as the hip, knee and shoulder. It occurs when a segment of bony tissue fails to receive the appropriate blood supply, because of the gaseous obstruction, and lead to both degeneration or b one tissue death (necrosis)

Symptoms

Unfortunately, there are no symptoms in the initial stages of the disease which affects many of those who do not seek help until they suffer fearsome complications.
The damage to the bones that will progress and their will soften and deform until eventually collapsing if the condition is not treated.

People affected might show the following symptoms:

• Arthralgia (joint pain): Typically in the groin when the hip is affected, this increases gradually with load weight. Suddenly worsen if the bone collapses. Restricting the range of joint movement.
• Antalgic march (Lameness): If the condition occurs in the lower extremities. Progressive impotence of the normal function in the affected extremity.

Treatment

The non-surgical treatment can delay the progress of aseptic necrosis, which includes the hyperbaric oxygen therapy in recompression chamber, which is supplying oxygen under high pressure, also known as “Hyperbaric Oxygen Therapy”.
The recompression chamber is a very large cylinder of metal and that has been adapted and clinically equipped with one (mono) or more beds for those affected External controls command both the recompression as well the gradual decompression of the affected until the elimination of micro-bubbles obstructive pulmonary is complete. The availability of portable chambers is common in the professional or recreational diving sites and facilities is fairly widespread and remain the first line of defense to counter the progressive effects of DCS. By its initials in English (Decompression Sickness. Vasodilators and blood thinners are jointly administered.

But besides that, in most cases, surgical treatment (surgery) could be eventually required. In very advanced cases total replacement of the joint, which includes the insertion of an implant or prosthesis is necessary.

Prevention

Prevention is, of course, the most important factor to avoid this condition or its resulting debilitating advanced lesions.
Dive following the safety rules and respect the times of permanence, speed of ascent and decompression stops set up to avoid decompression sickness.
In cases that diving was to be suddenly interrupted for unforeseen reasons as an emergency exit, the use of a recompression chamber should be considered to avoid complications.
If a hyperbaric chamber is NOT found on site, a “field” recompression, that is a controlled and monitored reinmmersion on the spot, at sea, of the affected diver intensively surveilled by the victim’s assistants at a depth no more than 15 feet is a LAST RESORT, while the surface personnel coordinates the logistics and eventual transportation to a properly equipped center. The time factor between the departure of the victim and hyperbaric oxygen therapy is critical, because the damage is progressive.

Special thanks to:
Dr. Eric M. Salado & Rick G. Hernandez