The opinion of the court was delivered by: John T. Curtin United States District Judge
Plaintiffs brought this action to recover damages for injuries suffered by plaintiff Eileen Donovan following spinal fusion surgery in February 2001. Mrs. Donovan's surgeon utilized the Centerpulse Spine-Tech Silhouette Spinal Fixation System ("SSF System"), an implant system of rods and screws used to correct spinal deformity and facilitate the process of spinal fusion. On July 27, 2001, x-rays of Mrs. Donovan's spine revealed that one of the six screws implanted in her vertebra had fractured. Mrs. Donovan underwent additional surgery on August 6, 2001 to have the SSF System removed, and alleges that she suffered permanent disabling injuries as a result of the broken screw. Plaintiffs have moved for partial summary judgment on liability (Item 64), and defendant has cross-moved for summary judgment (Item 70) and to preclude, pursuant to Fed. R. Evid. 702, the testimony of plaintiff's proposed expert witness (Item 79).
Plaintiffs commenced this action on May 9, 2003, alleging a single cause of action on behalf of Mrs. Donovan and a derivative cause of action on behalf of Mr. Donovan.*fn1
Specifically, plaintiffs alleged that Mrs. Donovan's injuries were caused "wholly or in large part to the interval fracture of the implanted screw, which resulted solely to (sic) the defective design and/or manufacture of the same screw, and due to no negligence on Ms. Donovan's part." Item 1, ¶ 11.
According to the parties' statements, pursuant to Local Rule 56.1, of facts not in dispute*fn2, Mrs. Donovan was injured in a fall on February 25, 2000. MRI imaging in March 2000 revealed bulging discs at L4-5 and L5-S1*fn3. Mrs. Donovan initially underwent conservative treatments, including physical therapy and cortisone injections, but they did not provide lasting relief. On February 21, 2001, Mrs. Donovan underwent a lumbar laminectomy and spinal fusion at L3-S1. The surgery involves the passage of screws into the pedicles*fn4 on either side of the spine, and the placement of a rod along the spine through the screws. Plaintiff's surgeon, Dr. Loubert Suddaby, utilized the Centerpulse SSF System. Following the surgery, Mrs. Donovan complained of numbness and pain in her left leg. X-rays of the operative site, taken on July 3, 2001, revealed a fracture of the right S1 implanted screw. On August 6, 2001, Mrs. Donovan underwent additional surgery to have the entire SSF System removed, except for a portion of the fractured pedicle screw imbedded in her spine. Dr. Suddaby determined that spinal fusion had not occurred.
Plaintiff Eileen Donovan testified in a deposition that prior to her surgery, she reviewed and signed a consent for treatment. Item 76, Exh. K ("Donovan Dep.") p. 70. She also discussed the surgery with Dr. Suddaby. Id., p. 74. Dr. Suddaby advised Mrs. Donovan that the surgery may not succeed. Id., p. 75. The consent form stated that a possible complication of the surgery is malfunction or breakage of the equipment, although Mrs. Donovan denied that Dr. Suddaby informed her of this. Id., pp. 80-81. Following the surgery, Mrs. Donovan experienced a "grinding" pain in the left side of her lower back. Id., p. 87. She also continued to experience a stabbing pain that she felt prior to the surgery, and that continued through her thigh and down her left leg. Id. Additionally, Mrs. Donovan lost feeling in her left kneecap, and the numbness has progressed down her leg. Id., pp. 88, 100. That pain has grown progressively worse since the surgery and has never resolved, although the grinding pain stopped after the implants were removed. Id., pp. 90-91. Following the second surgery, Mrs. Donovan did not return to Dr. Suddaby. Id., p. 102.
In support of their motion, plaintiffs submitted the deposition testimony of Dr. Suddaby. Item 64, Exh. H ("Suddaby Dep."). Dr. Suddaby stated that Mrs. Donovan was referred to him for numbness and weakness in her left leg following an injury. Id., p.14-15. He examined her on April 20, 2000 and found that she "had pain on movement of her spine in all spheres" and was "morbidly obese," meaning that the excess weight she carried was detrimental to her health and well-being. Id., pp. 15-16. On October 10, 2000, Mrs. Donovan reported to Dr. Suddaby that she had experienced no specific benefit from pain management and epidural cortisone injections. Id., p. 23. Dr. Suddaby discussed with Mrs. Donovan surgical interventions known as laminectomy and spinal fusion. He also discussed the risks of the surgery and advised Mrs. Donovan that obesity creates a risk of non-union of the fusion, a higher risk of infection, and makes the surgery technically more difficult for the surgeon. Id., p. 66. Mrs. Donovan nonetheless agreed to the surgery.
Dr. Suddaby performed Mrs. Donovan's spinal fusion surgery on February 21, 2001 and utilized the SSF System. It was a system Dr. Suddaby used in the past, and he was generally satisfied with it. Suddaby Dep., p. 42. Six screws were used in the procedure for Mrs. Donovan. Id., p. 52. Following the surgery, Dr. Suddaby saw Mrs. Donovan for follow-up care. She complained of pain, numbness, and hyperesthesia, or heightened sensitivity of the skin, in her left leg. Dr. Suddaby did not find this unusual, as that was the leg in which Mrs. Donovan experienced most of her symptoms prior to surgery. Id., pp. 60-62. Post operative x-rays revealed that the right screw was medially placed, meaning that "the screw is placed more towards the center of the midline of the spine than to the lateral part of the spine." Id., p. 64. However, Dr. Suddaby concluded that this medial position did not account for plaintiff's symptoms on the left leg. Id., p. 63. Dr. Suddaby further stated that medial placement of the screw can "irritate a nerve and cause pain or numbness or weakness," but the placement of the right sacral screw would not cause problems on the left leg. Id., p. 64.
In May 2001, Mrs. Donovan reported diminished reflexes in the right ankle and left knee. Suddaby Dep., p. 67. These findings indicated the "potential for irritation or dysfunction of one of the nerve roots that subtend those reflexes." Id., p. 67. Dr. Suddaby suspected that the absent right ankle reflex could be related to the medially placed right sacral screw, but Mrs. Donovan's fusion seemed to be progressing and she stated that she could live with the symptoms. Id., p. 68. Dr. Suddaby prescribed the use of a brace and an electromagnetic bone stimulator as part of her post-surgical care. Id., pp. 69-70. On July 7, 2001, Dr. Suddaby reviewed x-rays of Mrs. Donovan's lumbar spine and saw evidence of the fracture of one of the screws. Id., p. 72. He stated that a fracture of the screw can occur because of metal fatigue, weakness, or some other defect in the screw. Id. Dr. Suddaby stated that the most common reason for a screw fracture is the failure of the "fusion to support the bone" and explained that "the metal over a period of time will fracture from continued flexing and extending of the spine." Id., p. 73. In this case, Dr. Suddaby stated that the "fusion did not progress... meaning that the bones were not solid and immobile within a period of three to four months and with the progression of time, the metal eventually will fail." Id. Dr. Suddaby stated that he warned Mrs. Donovan of this risk, and saw no evidence of a defect in the metal screw itself or in its design, or in the SSF System. Id., pp. 73-74.
On August 6, 2001, Dr. Suddaby performed surgery to remove the spinal hardware. Suddaby Dep., p. 75. The right sacral screw was fractured at the midpoint of the shaft. Id. Part of the screw remained in the bone, as removal would have required the drilling away of additional bone. Id., p. 76. In his operative report, Dr. Suddaby noted "minimal fusion massed bilaterally," meaning less fusion than would have been expected over that period of time, and "residual lumbar instability." Id., p. 78. In his opinion, this was the cause of much of plaintiff's pain, coupled with spinal stenosis. Id., pp. 78-79. Dr. Suddaby stated that the instability of the spine was "a significant component" of plaintiff's postoperative pain, along with other "possible things such as perineural scarring and possible irritation of her nerve roots, inflammatory reasons" as part of the healing process. Id., p. 79.
In October 2001, Mrs. Donovan was still experiencing some pain, despite the removal of the hardware. Dr. Suddaby stated that Mrs. Donovan's post-operative pain was likely caused in part by the loose hardware, but that was not the only cause, as removal of the hardware did not rectify the problem. Id., p. 80. In Dr. Suddaby's opinion, plaintiff's pain was caused by the non-union of the fusion and continued instability of the spine, along with the other factors previously discussed. Id., p. 81. Dr. Suddaby also stated that the screw fragment in plaintiff's pedicle is not impinging on a nerve. Id., p. 86. Dr. Suddaby stated that it is "possible" that the fractured pedicle screw could have interfered with the union of the fusion generally, id., p. 114, or it was equally possible that it had nothing to do with the non-union. Id., p. 126.
Assuming compliance by plaintiff with post-operative instructions, Dr. Suddaby attributed the fracture of the screw to metal fatigue. He explained that it is a "race between the bone fusing and the metal fatiguing. That goes to say that in any of these fusion surgeries, if bony fusion does not occur, ultimately at some point in time it is expected that the instrumentation will fail. And exactly when that point is achieved is variable from human being to human being." Suddaby Dep., p. 122. Dr. Suddaby also explained that length of time before fusion is achieved depends on the activity and size of the person and the number of spinal levels fused. Id., p. 123. Dr. Suddaby stated that out of hundreds of spinal fusion surgeries he had performed over the years, he had seen approximately "half a dozen or more of these fractures...." Id., p. 84. Dr. Suddaby no longer uses the SSF System, and switched to a different spinal fusion system since the time of Ms. Donovan's surgery because others were easier to use. Id., p. 88. He has seen fractures of the pedicle screws in those systems as well. Id.
Plaintiffs also submitted the deposition testimony of Angela Hillyard, Director of Product Development for defendant Centerpulse. Item 64, Exh. K ("Hillyard Dep."). Ms. Hillyard testified regarding the testing of the pedicle screws for approval by the United States Food and Drug Administration ("FDA"). She stated that the average time for a spinal fusion to occur following surgery is 12 months, and that during that 12-month period, there would be between 1 and 2.5 million stress cycles on the component. Id., p. 37. A stress cycle is "the loading and unloading action on the screw construct or component." Id. For ease of reference, Ms. Hillyard compared one cycle to the bending and straightening of a paperclip. Id. The screws used in the SSF System were tested according to the American Society of Testing Materials ("ASTM") provisional standard PS 5-94 and draft standard F-04.25.03 and were tested to 5 million cycles. Id., pp. 38-41. If a product did not withstand at least one million cycles in testing, it is not likely to last the average 12 months for a fusion to occur. Id., p. 41. Ms. Hillyard stated that the product insert for the SSF System provides that the product is contraindicated for use in obese persons, but she is aware that the product is nonetheless used in obese patients. Id., p. 47. Ms. Hillyard also stated that ASTM testing standards are used to establish a ...