uman challenges, particularly war, breed solutions, technological innovation and ultimately advance our understanding of the physical world. World War II gave us atomic energy, while the Space Race gave us microwave ovens and pocket calculators. Likewise, the impact of war has advanced medicine myriad times throughout human history, particularly in our understanding of pain and its treatment.

Silas Weir Mitchell, M.D., a U.S. Civil War-era neurologist who devoted his life to the study of neuropathic pain, eloquently noted, “Long after the trace of the effects of a wound has gone, neuralgic symptoms are apt to linger, and too many carry with them throughout long years this final reminder of the battle-field.”¹ Besides being credited as the first modern physician to clinically describe causalgia, he was also ahead of his time in describing its treatment. He suggested inducing general anesthesia with ether to promote physical therapy for rehabilitation and first suggested the use of electrical stimulation utilizing a TENS-like device created by his contemporary, French neurologist Guillaume Benjamin Amand Duchenne.¹ He may also be the first physician to recognize opioid tolerance and hyperalgesia as it related to prodigious and ever-increasing, ineffective doses of morphia for treatment of neuropathic pain.

The current Middle East conflict has bred a number of solutions through technological innovation and has advanced our understanding of the physiology of pain. During the U.S. Civil War, mortality rates were higher than 50 percent.² World War II mortality rates from battlefield injuries averaged 40 percent. By the Vietnam war, this rate had dropped to 24 percent.² Current estimates for the Iraq and Afghanistan war are determined to be at less than 10 percent mortality for wounded U.S. casualties.³ While vital areas are protected, such as the chest, neck and head, extremity wounds are most prevalent, with orthopedic injuries approaching 50 percent.⁴ Casualties now surviving massive wounds inflicted by improvised explosive devices are stabilized at the front lines, and rapid helicopter evacuation facilitates transfer to higher echelons of care.

During the opening phases of the war, the casualty-receiving ships such as the U.S.N.S. Comfort saw few U.S. casualties because of the efficiency in stabilizing the wounded and flying them immediately to tertiary treatment facilities in Europe, such as the Army hospital at Landstuhl, Germany. Rapid evacuation, better armor and sophisticated forward-deployed fleet surgical teams have produced dramatically improved survival rates in U.S. casualties compared to previous wars. Additionally, challenges faced by deployed anesthesiologists have produced other dramatic advances that may change the way the physiology of pain is understood and treated in the future.

One such advancement is the aggressive mitigation of neuroplastic changes induced by acute pain through immediate and effective treatment. At the outset of the present conflict, the only pain medication available to forward-deployed units was morphine, a mainstay since the Civil War. Enterprising anesthesiologists, such as Chester “Trip” Buckenmaier III, M.D., Col., U.S. Medical Corps, recognized this shortcoming immediately. Necessity bred a solution: the application of regional anesthesia on the battlefield, spawning the next logical evolution — indwelling catheters placed at the front lines. To date, U.S. military anesthesiologists have placed well over 2,000 indwelling catheters in austere circumstances, far from the sterile environment of an operating room, with infection rates less than 1 percent, none of which were life-threatening.⁵ Many of the U.S. Army techniques for catheter placement rely on nerve stimulation. On the Navy and Marine Corps side, anesthesiologists were much less likely to find a nerve stimulator in the fleet surgical team gear but did find ultrasonographic devices such as the Sonosite 180 readily available. Patrick Boyle, M.D., Cmdr. (ret), Medical Corps, U.S. Navy, was one of the first anesthesiologists who applied this device to the practice of regional anesthesia, performing the first ultrasound-guided blocks at Al-Asad Airbase in the Anbar province of Iraq.

The legacy of forward-thinking acute pain management led to the development of the Military Advanced Regional Anesthesia & Analgesia, or MARAA, group. It is a tri-service collaborative group of anesthesiologists that makes recommendations about acute pain management in a battlefield environment. This collaboration has led to the development of a tri-service fellowship in regional anesthesiology hosted by Walter Reed Army Medical Center.⁶ Other practical innovations include the development of protocols, including the first use of I.V. patient-controlled analgesia onboard evacuation flights. Future directions may include the application of Ortho-McNeil’s new iontophoretic fentanyl delivery device, which will eliminate the need for I.V. access and may even replace injectable morphine by Special Forces units.

Chronic pain management delivery has also been advanced in the forward-deployed environment. Steven Cohen, M.D., Col., U.S. Medical Corps, has proposed and supported fluoroscopically guided interventions at echelon 3 facilities in Baghdad. Selective nerve root blockade for acute radiculopathies has allowed for rapid redeployment of troops sidelined by injury — this has been appreciated by the military as whole, which is presently struggling with workforce issues. Other contributions by chronic pain physicians include early use of neuromodulatory medications such as gabapentinoids and tricyclic antidepressants. While there are no compiled statistics to date, anecdotal evidence suggests that the benefits of this forward thinking may be leading to a lower incidence of phantom limb pain and complex regional pain syndromes. Indeed, recent studies indicate even a single dose of 1,200 mg of gabapentin preoperatively may reduce opioid use by 50 percent in the postoperative period.⁷ When a complex regional pain syndrome is identified, chronic pain physicians at tertiary military centers act aggressively. Recent case series indicate favorable results — including decreased opioid intake, better compliance with physical therapy and retention of military service — when spinal cord stimulation is applied early in the course of the disease.⁸

Recently, the governor of California broke his leg while skiing at Sun Valley. His travails were detailed explicitly in the press. Particularly poignant was his description of postoperative pain and limiting his narcotic intake. “I’ve never had this kind of pain after the surgery” and “you only want to take a little bit of medication because otherwise, you know, you maybe forget what you want to say and start slurring because medication has an effect,” he is quoted as saying.⁹ It is clear that Mr. Schwarzenegger did not have the benefit of a functioning regional anesthetic, but with the focused efforts of military anesthesiologists, civilian practice may yet change so that even the “Terminator” won’t have to complain of pain after surgery.

References:
1. Mitchell SW. Gunshot Wounds and Other Injuries of Nerves. Philadelphia: Lippincott, 1864.
2. Chambers JW, Editor-in-Chief. The Oxford Companion to American Military History. Oxford University Press; 1999:849.
3. Gawande A. Casualties of war – Military care for the wounded from Iraq and Afghanistan N Eng J Med. 2004; 351(24):2471-2475.
4. Nelson TJ, Wall DB, Stedje-Larsen ET, et al. Predictors of mortality in close proximity blast injuries during Operation Iraqi Freedom. J Am Coll Surg. 2006; 202(3):418-422.
5. Stojadinovic A, Auton A, Peoples GE, et al. Responding to challenges in modern combat casualty care: Innovative use of advanced regional anesthesia. Pain Med. 2006; 7(4):330-338.
6. Buckenmaier CC, Lee EH, Shields CH, Sampson JB, Chiles JH. Regional anesthesia in austere environments. Reg Anesth Pain Med. 2003; 28(4):321-327.
7. Dirks J, Fredensborg BB, Christensen D, et al. A randomized study of the effects of single-dose gabapentin versus placebo on postoperative pain and morphine consumption after mastectomy. Anesthesiology. 2002; 97(3):560-564.
8. Verdolin MH, Stedje-Larsen ET, Hickey AH. Ten consecutive cases of complex regional pain syndrome of less than 12 months duration in active duty United States military personnel treated with spinal cord stimulation. Anesth Analg. 2007; 104(6):1557-1560.
9. Associated Press News Pool Report, January 15, 2007.

Michael H. Verdolin, M.D., is former Director of Interventional Pain Management, Naval Hospital in San Diego. He is currently Medical Director, Pain Control Associates of San Diego, Chula Vista, California.