The Disabled List Informer

The pain in Chris Duncan ’s neck became too much to handle, and it is now being reported that he will undergo a rare (for athletes) Cervical disc replacement surgery on Monday and miss the remainder of the 2008 season. His future in baseball is uncertain at this time. Duncan has also had lumbar disc surgery, which in all likelihood means that he is physically predisposed to this type of malady.

According to ESPN.com, this surgery is believed to be among the first with professional athletes. I have personally treated a small number of patients with this procedure, with generally good but varied results. In general, 90% of patients who undergo Cervical disc replacement experience pain relief within 4-6 weeks.

The traditional Cervical fusion procedure, which utilizes a plate and screws, leaves the patient with significantly decreased mobility in the neck. This type of procedure would have certainly left Duncan unable to resume his career. In addition, a fusion typically will result in painful dysfunction of spine segments above and below the surgical site in the future. The disc replacement surgery, though fairly new and recently receiving FDA clearance (and expensive: $15,000 or more for the implant alone), at least leaves open the possibility for a return as it allows for greater post-op mobility of the neck.

According to Noam Stadlan, M.D., of the Chicago Institute of Neurosurgery and Neuroresearch, “Compared to spinal fusion, this surgery allows patients to maintain normal neck motion, and study has shown a lower rate of additional surgery for degeneration of adjacent segments. Unlike with fusion, patients who’ve received the disc don’t have to bother with a hard collar following surgery.”

Dr. Dean Karahalios, CINN neurosurgeon states, “Study results show that artificial cervical disc patients regain function faster, and have a higher rate of neurological success as measured by muscle tone, strength, sensation, as well as responsiveness of reflexes than those who undergo spinal fusion. Furthermore, the study demonstrated that at two year follow-up the overall success rate for the artificial disc group was 79.3% compared to the fusion group at 67.8%. These reasons are compelling enough for potential candidates to consider the option of an artificial disc.”

With the news that this is the procedure being performed, it indicates that his herniation was likely a massive left-sided posterior-lateral herniation causing significant pain and motor impairment of the left arm. The concerning thing here isn’t that he had a herniation, it is that Duncan was feeling pain radiating into his arm in addition to weakness in his left arm. This signifies that the disc was severely herniated and was possibly compressing the central canal and cord.

The exact disc is between the C5 and C6 vertebrae, which, when herniated, elicits pain and occasionally strength deficits to the neck, lateral shoulder/forearm, thumb, index and middle finger (though not all are always present). In particular, there is typically weakness of the Deltoid muscle, which abducts the shoulder (raises it up to the side), as well as the Biceps, which flexes the elbow, supinates the forearm, and flexes the shoulder (this muscles also receives input from C6 level, and is usually less involved than the Deltoid).

While he should regain his overall function, there are never any guarantees - especially with spine surgery. It is uncertain how he will bounce back from this surgery, but Duncan is tough as nails and I would not bet against him making a comeback in ‘09. This surgery certainly casts a shadow over a possible return, however. Given that the motor involvement is in his left arm and shoulder, he should not have any limitation with throwing, but his hitting effectiveness - notably with his power - will be the major test.