OPINION
I. Introduction
This is a medical malpractice case in which appellants Thomas and Patricia Wiggs (“the Wiggs”) claim negligent acts of appellees All Saints Health System d/b/a All Saints Episcopal Hospital/Fort Worth and Drs. George Crisp, Allen Kent, and Robert Lagon caused Mr. Wiggs’s loss of vision following back surgery. The Wiggs offered the testimony of their designated experts, Drs. Richard Watkins and James Key, on the alleged cause of Mr. Wiggs’s condition, which they identified as ischemic optic neuropathy (“ION”). According to Dr. Watkins, prolonged hypertension and significant blood loss during Mr. Wiggs’s surgery resulted in hypoper-fusion and lack of blood and oxygen to his optic nerves, causing ION.
On the appellees’ motion, the trial court excluded the medical causation testimony of the Wiggs’ experts as scientifically unreliable. The trial court then entered a final take-nothing judgment in favor of appel-lees, on the basis that the Wiggs had no evidence of causation. In two issues, the Wiggs contend the trial court erred by excluding their medical causation testimony and granting judgment against them for lack of such testimony. We affirm.
II. Standard of Review for Expert Testimony
An expert may testify on scientific, technical, or other specialized subjects if the testimony would assist the fact finder in understanding the evidence or deter
III. The Reliability op the Experts’ Causation Testimony
In issue one, the Wiggs contend that the trial court erred by finding that they failed to show a reliable scientific basis for the causation testimony offered by their experts, by excluding the medical causation testimony of their experts as scientifically unreliable, and by granting judgment against them for lack of causation testimony. Specifically, the Wiggs claim that the trial court excluded the testimony without reference to the applicable guiding rules or principles, constituting an abuse of discretion which resulted in the rendition of an improper judgment in this case. In issue two, the Wiggs argue that the trial court also erred if the medical causation testimony was excluded for any reason other than scientific unreliability. 1 '
A. Standard of Review
Expert testimony must be based on a reliable foundation of scientific or professional technique or principle.
Robinson,
In
Robinson,
the Texas Supreme Court set forth six factors, now known as the
Daubert/Robinson
factors, to aid courts in determining whether scientific testimony is reliable: (1) the extent to which the theory has been tested; (2) the extent to which the technique relies on the expert’s subjective interpretation; (3) whether the theory
Following
Robinson,
the Texas Supreme Court addresses the issue of scientific and nonscientific evidence and determined that while all expert testimony must be reliable before it may be admitted, the factors affecting reliability as outlined in
Robinson
are not applicable to all expert testimony.
Gammill,
Still, in discharging its duty as “gatekeeper,” the trial court is in the best position to decide whether some or all of the
Daubert/Robinson
factors and/or the
Gam-mill
general reliability test should be applied to determine the reliability of the expert’s testimony.
Gammill,
B. Application
On appeal, the Wiggs argue that the trial court incorrectly applied the
Dau-bert/Robinson
factors to this ease because their experts’ opinions were based on the experts’ knowledge, skill, experience, training, and education.
See Gammill,
In their motions to exclude, appellees asserted that the opinions of Drs. Watkins and Key lacked a rehable scientific basis because they did not conform to the analysis under the
Daubert/Robinson
factors. While it is true that the trial court agreed with appellees in the result, the trial court’s order excluding the testimony does not specify what analysis the trial court applied in assessing the reliability of the testimony.
2
Moreover, a review of the record indicates that regardless of the standard the trial court applied in excluding the testimony, it did not abuse its discretion in determining that the experts’ testimony was scientifically unreliable in this case.
3
See Gammill,
Analyzing the evidence in this case in light of the Daubert/Robinson factors, we conclude that the evidence shows that the theory relied on by the experts has not been sufficiently tested, is controversial within the relevant scientific community, requires subjective interpretation, and has not been subjected to sufficient peer review. Moreover, the evidence shows that the experts failed to sufficiently rule out other causes. On appeal, the Wiggs fail to argue that their experts’ causation testimony was reliable under the Daubert/Robinson factors and do not attempt to contradict the evidence cited by appellees to establish unreliability under the factors. The trial court, therefore, did not abuse its discretion in determining that the experts causation testimony was scientifically unreliable under the Daubert/Rob-inson factors.
2. Gammill’s Analytical Gap Test
In applying
Gammill’s
“analytical gap” test, which the Wiggs contend is required, we must analyze the underlying data forming the basis for the expert’s opinion.
a. Dr. Watkins’s Experience and Training
Dr. Watkins’s opinion was purportedly based on his qualifications as an anesthesiologist, his experience in providing anesthesia care to more than 7,000 patients during surgery, a review of Mr. Wiggs’s medical records, and medical literature. The quantity of Dr. Watkins’s “experiences” in cases of this nature is insufficient to render his opinion on causation reliable. Of all his cases, less than one percent involved providing anesthesia care to patients undergoing spinal surgery. Moreover, Dr. Watkins has never administered anesthesia in a case like the present one, where the patient was undergoing multiple procedures during one surgery, and where the neurosurgeon did not become involved in the surgery until after the surgery had begun.
The quality of Dr. Watkins’s experience does not make his opinion on the cause of ION any more reliable. Of the 7,000 patients to whom he has administered anesthesia, only one “may have had” ION. “Certainly, if [an expert] is primarily depending on his experience to support his opinion, he would have to have seen it
b. Dr. Key’s Experience and Training
Dr. Key’s opinion was purportedly based on his qualifications as an ophthalmologist, his experience in evaluating and diagnosing ION, his examination of Mr. Wiggs, and his knowledge of medical literature dealing with ION. Dr. Key’s experience as a general ophthalmologist does not make his opinions on causation reliable. Approximately 30% of his clients are contact lens patients, 30% are glasses patients, and 20% are cataracts patients. The remaining 15-20% are a general mix consisting mostly of acute problems, such as red eyes, discharge, pain, and retinal problems. Moreover, since becoming a doctor in 1970, Dr. Key has diagnosed only 40 post-surgery ION patients. Although this experience might provide a basis for Dr. Key to express an opinion on diagnosing and treating ION, it does not provide a reliable basis for him to render an expert opinion on what caused a particular patient’s ION. Additionally, Dr. Key likewise has no special training regarding ION and its causes. Finally, he has conducted no studies or research concerning ION.
c. Medical Literature
If a medical expert seeks to support his opinion on causation with medical literature, he must base his opinion on a “broad reading of the medical literature.”
Minn. Min. & Mfg. Co. v. Atterbury,
Moreover, none of the medical literature cited by the Wiggs concludes, as posited by Drs. Watkins and Key, that “prolonged hypotension and significant blood loss” actually causes ION. Instead, the literature they cite demonstrates that the causes of ION are simply unknown in the scientific community. For example, the journal article entitled “Unilateral Blindness After Prone Lumbar Spine Surgery,” authored in 2001, discussed the case of ION occurring after an uneventful spine operation in a relatively healthy man. The article noted that “[cjlearly, other factors, intrinsic either to the patient (e.g. ocular vascular anatomy, coexisting illness) or to the operation ... may have important contributory roles in the development of postoperative visual deficits.” The article concludes by stating that “despite the apparent increase in the incidence of peri-operative visual deficits over the past 5-10 yr, we do not know the precise etiologic factors, nor do we know how to prevent it.”
Another journal article furnished by the Wiggs, entitled “Postoperative Visual Loss, Still No Answers — Yet,” authored in 2001, similarly demonstrates that causation of ION remains unclear. It notes that post-operative vision loss has “evoked controversy,” and asks the rhetorical question, “Is it a preventable injury?” The article
In summary, the doctors’ experience and training in their respective fields and the medical literature did not form a reliable basis for their opinions as to the cause of Mr. Wiggs’s post-operative vision loss. When the bases for the experts’ opinion are unreliable, their opinions are also unreliable. Havn
er,
IV. CONCLUSION
Since the Wiggs presented no causation evidence other than that of Drs. Watkins and Key, and the trial court ruled their testimony was not rehable, an essential element of the Wiggs’s claims is not supported by evidence.
Marvelli,
DAUPHINOT, J., dissents without opinion.
Notes
. The Wiggs explain that they have included this issue and addressed the experts' qualifications and the relevance of their opinions out of fear that the broad nature of appellees’ motion might allow this court to find the trial court did not abuse its discretion by excluding the experts' testimony for a reason other than scientific unreliability. However, the trial court specifically stated that the lack of scientific reliability was the reason it excluded the testimony.
. "[A]fter careful reconsideration of the various motions, [the Wiggs] response, case law cited and arguments of all interested counsel, the Court finds that it should exclude any causation testimony from [the Wiggs’] experts claiming that the surgery performed for [Mr. Wigg] allegedly caused [ION] because [the Wiggs] cannot show a reliable scientific basis for the opinions offered by their expert[s].”
. The Wiggs cite no cases, and we find none, holding that it is an abuse of discretion for the
