Source: https://wcc.state.ct.us/crb/2008/5164crb.htm
Timestamp: 2019-04-21 05:10:59+00:00

Document:
The claimant was represented by Kevin W. Coombes, Esq., McCarthy, Schuman & Coombes, 61 Russ Street, Hartford, CT 06106.
The respondent was represented by Philip Schulz, Esq., Assistant Attorney General, Office of the Attorney General, 55 Elm Street, P.O. Box 120, Hartford, CT 06141-0120.
This Petition for Review from the November 11, 2006 Finding and Award of the Commissioner acting for the Eighth District was heard June 15, 2007 before a Compensation Review Board panel consisting of the Commission Chairman John A. Mastropietro and Commissioners Amado J. Vargas and Scott A. Barton.
JOHN A. MASTROPIETRO, CHAIRMAN. The respondent has petitioned for review from the November 6, 2006 Finding and Award of the Commissioner acting for the Eighth District, arguing on appeal that the trier erred by authorizing three-level disc replacement surgery. We remand the trial commissioner’s decision after clarifying the standard of scientific evidence needed to approve an unconventional surgical procedure.
The claimant injured her low back on July 2, 1985. She has treated with and been tested by many doctors, but has not had back surgery, which the respondent declined to authorize in 1987. In 2003, she was referred to Dr. Yue for consideration of disc replacement surgery, and was diagnosed with degenerative disc disease (DDD) at three levels. Dr. Yue favored surgery, but advised the claimant that it would have to be delayed until the Food and Drug Administration (FDA) approved the ProDisc device. Dr. Zack, a family practitioner who had treated the claimant on many occasions, agreed with Dr. Yue’s surgical recommendation. Dr. Lange, the respondent’s examiner, opined that the claimant was not a good candidate for surgery, and questioned the lack of FDA approval for ProDisc usage. He believed that the claimant currently has a sedentary work capacity.
The claimant testified that her injury has caused her intractable pain, difficulty walking, and numbness in her legs. She has not worked since low back symptoms forced her to leave her part-time job as a bus dispatcher in 1997. According to the medical reports in evidence, she has been relying for many years on supervised doses of pain medication, including narcotics such as OxyContin, morphine, and transdermally-delivered fentanyl, and she has developed depression and obesity as a result of chronic pain. See, e.g., February 24, 2005 report of Dr. Zack, Claimant’s Exhibit M. If nothing is done to alleviate her constant low back pain, she (at age 46) believes that she will soon need a wheelchair, and will never be able to work. The trier noted that she appeared to be physically uncomfortable sitting through the formal proceedings, and has undergone a gastric bypass to facilitate weight loss in preparation for surgery. In his conclusions, the trier found that the opinions, objective testing and surgical recommendation of Dr. Yue were reasonable and credible, and authorized him to perform the disc replacement procedure at his Yale medical facility. The respondent has petitioned for review from that decision, and has also filed a Motion to Submit Additional Evidence.
The additional evidence, a deposition of Dr. Yue that was taken on February 8, 2007, is offered in response to a February 13, 2006 note from Yale Orthopaedics to the claimant’s attorney that was admitted over the respondent’s objection, which the trier described as “appear[ing] to confirm that the use of ProDisc hardware has been approved by the FDA.” Findings, ¶ 19.1 According to the respondent’s counsel, the note2 was handwritten on a fax cover sheet, and was “an unsigned and unauthenticated hearsay statement from someone named ‘Laura’ in Dr. Yue’s office,” rather than a medical report. Motion, p. 1. Counsel further explains that Dr. Yue was not deposed prior to the formal hearing because the respondent had already offered evidence that the proposed three-level surgery had not been approved by the FDA, and counsel did not expect the fax cover sheet to be admitted into evidence. Dr. Yue’s deposition testimony is being offered to confirm that the FDA has not approved multi-level disc replacement surgery.
We now move forward on the factual premise that the trial commissioner approved the claimant’s request for three-level disc replacement surgery after finding that (1) the ProDisc device that Dr. Yue intends to use has been approved by the FDA for use at one level, and (2) it has not been approved by the FDA for use at three levels. The respondent argues that the trier exceeded his authority by finding that this surgical procedure was reasonable and necessary even though it has not been FDA approved, it carries with it significant cost and health risks, and a private health insurer would be entitled to deny this procedure as experimental under § 38a-483c(b) and § 38a-513b(b).
The Workers’ Compensation Act is a statutory compromise of legal rights that governs injuries arising out of and in the course of employment. Klapproth v. Turner, 156 Conn. 276, 279 (1968). It requires the employee to surrender the common-law right to sue the employer for damages in favor of “a prompt, efficient, simple and inexpensive procedure for obtaining benefits related to employment.” Pietraroia v. Northeast Utilities, 254 Conn. 60, 74 (2000), quoting Middletown v. Local 1073, 1 Conn. App. 58, 65 (1983), cert. dismissed, 192 Conn. 803 (1984); Casey v. Northeast Utilities, 249 Conn. 365, 378-79 (1999). Insofar as is possible, the Act seeks to restore the injured employee to the status of a healthy, productive member of society. Bowen v. Stanadyne, Inc., 2 Conn. Workers’ Comp. Rev. Op. 60, 64, 232 CRD-1-83 (June 19, 1984).
Upon learning of an injury, § 31-294d C.G.S. requires an employer to furnish medical and surgical aid “as the physician or surgeon deems reasonable or necessary.”5 In general, we have defined reasonable and necessary medical care as “that which is curative and remedial. Curative or remedial care is that which seeks to repair the damage to health caused by the job even if not enough health is restored to return to work.” DeFelippi v. Wal-Mart Stores, Inc., 4349 CRB-5-01-1 (January 15, 2002)(citation omitted). This may include preventative care; Doe v. Stamford, 241 Conn. 692 (1997)(police officer exposed to infectious diseases was entitled to reasonable testing and treatment); and therapy designed to eliminate pain or prolong life, even if there is a strong chance that it will not be effective. See, e.g., Thomas v. Mohegan Sun Casino, 4754 CRB-2-03-11 (February 18, 2005) (intradiscal electrothermal surgery on torn disc annulus confirmed despite questions about its effectiveness); Irizarry v. Purolator Courier Corp., 4382 CRB-4-01-4 (May 2, 2002) (estimated 60% chance that authorized back surgery would improve patient’s quality of life); Cirrito v. Resource Group Ltd. of Conn., 4248 CRB-1-00-6 (June 19, 2001) (epidural steroid injections allowable even if estimated efficacy rate was only 5%). The reasonableness of treatment also depends on the circumstances. Given the invasiveness, novelty, cost and degree of risk inherent in a three-level disc replacement, a commissioner should weigh the evidence carefully before approving it as “reasonable” and “necessary.” “Whether a proposed surgical procedure is reasonable . . . is a question of fact for the commissioner to resolve.” Pagliarulo v. Bridgeport Machines, Inc., 20 Conn. App. 154, 158 (1989). “ Though medical evidence takes center stage in making that decision . . . the trier may also consider surrounding circumstances, such as the claimant’s age, medical history, the effectiveness of prior treatment, and as stated in [Acquarulo v. Botwinik Bros., Inc., 139 684, 690 (1953)], whether the procedure involves real danger and suffering without fair assurance of improved or restored health.” Jolicoeur v. Duncklee, Inc., 5150 CRB-2-06-10 (November 8, 2007).
Once a device is being sold legally, the FDA’s approval to use it in a particular surgical procedure could be used as evidence that said use is medically viable.8 See note 6, supra. However, such a use-specific marketing approval is not a prerequisite to identifying a proposed medical procedure as “reasonable and necessary,” given the purpose of the FDA and the scope of its authority. Once a device has been FDA-approved, “off-label” uses often emerge that vary from the specific use cleared by the FDA. Washington Legal Foundation v. Henney, 202 F.3d 331, 332 (D.C. Cir. 2000). Although a manufacturer may not introduce a device into interstate commerce with the intent that it be used for an off-label purpose; 21 U.S.C. § 331(a); it is understood that “off-label” usage of medical devices is “an accepted and necessary corollary of the FDA’s mission to regulate in this area without directly interfering with the practice of medicine.” Buckman Co. v. Plaintiffs’ Legal Committee, 531 U.S. 341, 350 (2001)9; Washington Legal, supra, 332-33; Weaver v. Reagen, 886 F.2d 194 (8th. Cir. 1989)(FDA non-approval of labeling for a particular use is not always indicative of uses of product that are considered appropriate within the medical and scientific community).
“A physician may prescribe a legal [device] to serve any purpose that he or she deems appropriate, regardless of whether the [device] has been approved for that use by the FDA.” Washington Legal, supra, 333. This principle is codified in 21 U.S.C. 396, which states that nothing in the Food, Drug and Cosmetic Act “shall be construed to limit or interfere with the authority of a health care practitioner to prescribe or administer any legally marketed device to a patient for any condition or disease within a legitimate health care practitioner-patient relationship.” Manufacturers remain prohibited from promoting unapproved uses for legally marketed devices.10 See, e.g., Ortho Pharmaceutical Corp. v. Cosprophar, Inc., 32 F.3d 690 (2nd Cir. 1994)(prescription drug that was FDA-approved only for treatment of acne could not be promoted for treatment of photodamaged skin, but FDA permitted doctors to prescribe it for this purpose).11 Thus, the absence of FDA approval for a physician’s proposed “off-label” use of a legally marketed device should not be treated as a proxy for a factual determination that the “off-label” use would be unreasonable, even though the FDA-approval history and labeling of the device may in some cases provide valuable evidence of fitness or unfitness for a suggested use.
The respondent also cites statutory standards in § 38a-483c and § 38a-513b C.G.S., which require individual and group health insurers in Connecticut to define the extent of their coverage for experimental treatments. A procedure, treatment or drug that has successfully completed a phase III clinical trial of the FDA may not be denied as experimental. Also, a terminally ill person with a two-year or lower life expectancy whose treatment is so denied may obtain an expedited appeal, which must be decided based on the medical efficacy of the treatment. The reviewer may consider whether the treatment has been approved by the National Institutes of Health or the American Medical Association, whether (if a drug) it is listed in one of several Drug Information and Evaluation guides, or whether it is currently in a phase III clinical FDA trial.
The Workers’ Compensation Act already recognizes the value of health care industry standards in many areas. This Commission’s fee schedule (see § 31-280(11)) and billing and payment guidelines (as per § 31-280(26)) utilize Current Procedural Terminology codes, which are widely used in the health care industry to describe medical and surgical services, and identify procedures that reflect contemporary medical practice and are commonly performed by physicians (while also creating a supplementary temporary coding system to track the use of new and emerging technologies). We have also been directed to implement in our fee schedule (as of April 1, 2008) the Medicare resource-based relative value scale and the Correct Coding Initiative used by the Centers for Medicare and Medicaid Services.13 Public Act 07-31. For a workers’ compensation commissioner, signs that a procedure has been incorporated into standard medical practice provide considerable assurance that it is considered scientifically viable and medically effective.14 See State v. Porter, 241 Conn. 57, 84-85 (1997) (general acceptance of scientific methodology will normally ensure that conclusions derived from that methodology are admissible in court), cert. denied, 523 U.S. 1058 (1998).
When a dispute arises in this forum over a less conventional diagnostic method or treatment, the commissioner must carefully examine the methodology underlying the proponent health care provider’s opinion. For example, assessments of permanent partial impairment are frequently based on the American Medical Association’s Guides to the Evaluation of Permanent Impairment, which are widely used by physicians and are considered “a well-established source of authority.” Safford v. Brockway, 262 Conn. 526, 533 (2003). Our law does not require doctors to follow the Guides; Id.; Napolitano v. Bridgeport, 4388 CRB-4-01-5 (September 6, 2002); and other methods of measuring impairment may be proposed. See, e.g., Ricigliano v. Rex Forge, 3476 CRB-6-96-11 (April 8, 1998)(claimant’s physician challenged restrictiveness of AMA method of measuring binaural hearing loss), aff’d, 53 Conn. App. 158 (1999), cert. dismissed, 252 Conn. 404 (2000). However, to qualify it as competent evidence, the proponent of another diagnostic method for assessing permanency must explain how it measures the percentage of loss of use of a scheduled body part. Safford, supra; Landry v. Light Metals Coloring Co., 4514 CRB-6-02-4 (April 3, 2003); see Barton v. Ducci Electrical Contractors, Inc., 4374 CRB-6-01-4 (March 25, 2002)(20% rating on several scheduled body parts improperly extrapolated rating for 20% loss of use of burned skin to each body part, without taking into account its overall function); Bilotta v. Connecticut Natural Gas Corp., 4106 CRB-1-99-8 (October 5, 2000) (permissible to assess effect of unscheduled body part on patient’s overall function prior to applying AMA guidelines).
Evaluating the appropriateness of a proposed medical treatment is a delicate task. While respecting the complex diagnostic and outcome-predictive skill that is central to a physician’s expertise, a workers’ compensation commissioner must assess the credibility of the evidence supporting the various treatment options and decide which is the most reasonable under all of the circumstances. See Tartaglino v. Department of Correction, 55 Conn. App. 190, 195 (1999), cert. denied, 251 Conn. 929 (1999); Duddy v. Filene’s (May Department Stores Co.), 4484 CRB-7-02-1 (October 23, 2002). In doing so, the trier has a lot of latitude. The ordinary rules of evidence are not binding in this forum, allowing a commissioner to make inquiry through testimony and records in the manner most likely to ascertain the parties’ rights. Section 31-298. Further, Connecticut Code of Evidence § 7-4 itself allows a physician’s expert opinion to be based on facts or data from outside sources, as long as that type of data is reasonably relied on by other physicians as a foundation for opinions. Carusillo v. Associated Women’s Health Specialists, 72 Conn. App. 75, 86 (2002)(citations omitted); see also, George v. Ericson, 250 Conn. 312, 317 (1999) (admissibility of physician’s opinion is governed by same standards that govern testimony of expert witnesses generally).
This procedural latitude regarding the mechanics of admitting evidence into the record does not diminish the quality of medical evidence needed to create a scientifically valid factual foundation, however. A commissioner is best able to decide whether an innovative surgical procedure is reasonably assured to restore a claimant’s health when the record contains a detailed evidentiary foundation. We therefore articulate this standard: in the case of a contested surgical procedure that is not well-established in the medical community, the evidence must include enough information for the trier to grasp the concepts and methods that support the procedure, and to anticipate that it will be effective for individuals comparable to the claimant. See Maher v. Quest Diagnostics, Inc., 269 Conn. 154, 173, 180 (2004)(requiring case-by-case assessment of evidentiary admissibility for cervical cancer “doubling time” evidence in negligence action). Just as trial courts are expected to do more than merely rely on an expert witness’ belief that a methodology is reliable; Id., 182, citing State v. Porter, 241 Conn. 57 (1997); a commissioner must also take steps to verify that a physician’s methodology is reliable, and relevant to the case. The novelty of an unconventional and controversial suggestion for treatment will not render the underlying medical opinion incompetent if it is derived from a valid scientific method, even if other valid methodologies lead to contrary recommendations. See Porter, supra, 81-83 (1997)(rejecting admissibility test for scientific evidence premised solely on “general acceptance” in relevant scientific community, in favor of test articulated in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993)). As always, the trier of fact need not explain why one methodology is more persuasive than another. See Admin. Reg. § 31-301-3 (finding should not contain reasons for trier’s conclusions, which better suit a memorandum of decision).
Drawing from our opinion in Cabral v. Metropolitan District Employees, 3770 CRB-1-98-2 (May 13, 1999)(commissioner adopted opinion on permanency based on a controversial diffusion capacity test), and our Supreme Court’s opinion in Porter, supra, we observe that our courts do not use a generic, mechanical test to assess the admissibility15 of scientific evidence, instead favoring a flexible, overarching approach using factors whose relevance varies on a case-by-case basis. Porter, supra, 80; Maher, supra, 168. In the workers’ compensation setting, methodological issues that are relevant to the scientific validity of evidence might include the quality of testing and peer review given to the reasoning or technique, its known and potential rate of error, to what degree conclusions rely on subjective assessments rather than objectively verifiable criteria, and the background and reputation of the doctor. This is not a checklist. Other factors may be relevant in addition to, or in lieu of, these factors, depending on the specific context.16 Of course, it is up to the parties to provide evidence supporting, challenging, or comparing proposed theories of treatment in order to establish a factual record. A trial commissioner is not expected to spontaneously develop critical methodological analyses that would help evaluate the scientific methods that underlie this type of evidence.
Here, several doctors testified or implied that the concept of three-level disc replacement surgery was valid. Both Dr. Yue and Dr. Zack recommended it for the claimant as a remedy for discogenic pain, while Dr. Lange expressed support for the concept of three-level artificial disc replacement and the notion that synthetic discs help prevent degeneration at adjacent disc levels by maintaining motion, even though he doubted it would be effective for this claimant. Respondent’s Exhibit 1, February 28, 2006 Transcript, pp. 18, 30-31. None of the doctors directly discussed studies reporting on multiple-level disc surgery except for Dr. Yue, who primarily focused on the results of the FDA approval process. He stated on March 8, 2006 that, upon FDA approval for single-level use, it would be acceptable to use the ProDisc in “off-label” fashion if the option exists. Claimant’s Exhibit K.
Dr. Yue also stated that two-level lumbar disk replacement would be officially approved within 16 months (as that procedure was the subject of a multicenter FDA study concurrent to the single-level ProDisc replacement study), while “[t]hree-level lumbar disk replacement will not be officially approved for approximately 25 years until the downgrade FDA classification occurs on the ProDisc device itself.” Id. We observe that, to date, the FDA has not approved two-level lumbar disk replacement with the ProDisc. See n.4, supra. Because the trier did not indicate that he was relying on this assertion as a factual underpinning of his approval of the three-level procedure, that discrepancy is not reversible error in and of itself. It remains part of the larger context, however, insofar as it fails to reflect the presence of clinical evidence supporting this use of the ProDisc.
In his March 28, 2006 report, Dr. Yue also referred to his own journal articles (which were not in evidence) demonstrating that ProDisc could be used at up to five levels in one person. Claimant’s Exhibit K. An expert witness may refer to outside studies in forming an opinion; Carusillo, supra; which, in this case, would simply be an extension of Dr. Yue’s own professional opinion, the studies being his own. The substance of the articles was not in evidence. On May 3, 2006, Dr. Yue reported that the ProDisc had been provisionally approved for single-level usage between L3 and S1, and that he could use it at multiple levels as long as he thought it would be medically beneficial for the patient, and she consented to bear the additional risk due to multilevel surgery. Claimant’s Exhibit L. Dr. Yue also supported the practice of multi-level disc replacement surgery by opining that individuals whose MRI appearance was similar to that of the claimant had tended to do well following the surgery. Claimant’s Exhibit G.
There is no discussion of other clinical evidence addressing the soundness of the multiple-level disc replacement procedure. A peer review report by a neurosurgeon, Dr. Dila, asserts that three-level lumbar artificial disc replacement is not indicated, because it is not approved by the FDA and is not supported in clinical trials. Respondent’s Exhibit 2. However, the report does not say to which clinical trials Dr. Dila is referring, or if he questions the procedure because no three-level trials have been conducted. Claimant’s Exhibit O is a printout of an article from the Spine-health.com website. It describes the ProDisc and discusses two studies that support the effectiveness of the device. There is no information about the authors, and the exhibit itself contains a disclaimer stating that the information available on Spine-health.com “is not intended as a substitute for medical professional help or advice.” Despite the principle that “[e]vidence is admitted not because it is shown to be competent, but because it is not shown to be incompetent;” Higgins v. Karp, 243 Conn. 495, 505 (1998); and the absence of a formal hearing transcript to tell us how the parties approached the admission of this exhibit, we cannot read this article as being an authoritative source of information without evidence to back up that authority. Thus, the article does not serve as competent expert scholarship.
On review, this board must be able to identify scientifically tenable reasoning in the record that supports the medical evidence. Beyond that, we defer to the trier’s factfinding discretion. Cabral, supra. The record in this case leaves many doubts about the proposed surgical intervention, there being little evidence to show the clinical success of multi-level artificial disc replacement in treating discogenic back pain, both generally and in a workers’ compensation context. Compare Jolicoeur, supra (testimony of Dr. Yue raised grounds supporting finding that proposed four-level lumbar disc replacement procedure was too risky). To enable the trier to evaluate this surgery with confidence and protect the claimant’s interests, the record must be strengthened with scientifically sound evidence supporting the procedure, as we have set forth in part II of this opinion. Currently, there is insufficient evidence to support the trier’s conclusion in ¶ c authorizing surgery. We thus order a remand for the limited purpose of addressing the scientific validity of three-level disc replacement surgery for individuals comparable to the claimant, which will demand the introduction of scientifically competent evidence. If evidence favoring the procedure is found to be methodologically sound and credible, the claimant’s surgery shall be authorized, based on the trial commissioner’s findings.
To that end, the subordinate findings regarding the claimant’s medical condition stand, as they are supported by Dr. Yue’s reports. He reported in 2003 that the claimant’s MRI showed DDD at L3-4, L4-5, and L5-S1, with early dessication (hydration loss) and minimal loss of disc height. The claimant described her pain as constant and interfering with normal life activities, following years of ineffective conservative treatment. Claimant’s Exhibit C. Dr. Yue opined that claimants with her MRI appearance had tended to do well following disc replacement surgery. Id. He also stated that she had been informed of the risks of the surgery, such as nerve damage, pain, paralysis, reoperation and hardware failure. Claimant’s Exhibit J.
Though Dr. Lange stated that he opposed operating on this claimant based on her heavy narcotic use, her pain at L2-3, and his belief that her functional capacity would not change; Respondent’s Exhibit 1, pp. 12-20; other reports counter those opinions. Dr. Yue explained that the lumbar discogram indicating substantial pain at L2-3 was not corroborated by the MRI, indicating that the L2-3 disc could be rehabilitated by disc replacement at the lower three levels. Claimant’s Exhibit I. The lumbar spine CT scan also identified only mild degeneration at L2-3, with more severe degeneration at lower discs. Claimant’s Exhibit G. Dr. Yue further opined that the claimant would return to work six to eight weeks after the operation. Claimant’s Exhibit C. As for narcotic use, Dr. Zack opined that the surgery would minimize the claimant’s need for chronic medications that were potentially damaging to her liver. Claimant’s Exhibit M. Dr. Zack also stated on August 14, 2006 that time was of the essence regarding surgery due to risk of osteoporosis because of premature ovarian failure. Claimant’s Exhibit N. These issues fell squarely within the trier’s discretionary authority to resolve disputes between physicians, and we cannot reverse such credibility assessments on appeal.
4 As an evidentiary matter, we note that federal statutes and regulations issued thereunder may be the subject of judicial notice by a court of appeal. Atlantic Richfield Co. v. Canaan Oil Co., 202 Conn. 234, 246 (1987); Powers v. Powers, 186 Conn. 8, 10 (1982). In turn, 44 U.S.C. § 1507 provides that the publication of a document in the Federal Register is sufficient to give notice of the contents of that document to anyone subject to or affected by it, and “shall be judicially noticed.” On January 26, 2007, at Volume 72, p. 3863 of the Federal Register (Dept. of Health and Human Services, Centers for Medicare and Medicaid Services), the FDA published a list of products whose pre-market applications had been approved by the agency. That list includes the application by Synthes Spine Co. for the ProDisc-L Total Disc Replacement, which was approved on August 14, 2006.
The publication also explains, “In the Federal Register of January 30, 1998 (63 FR 4571), FDA published a final rule that revised 21 CFR 814.44(d) and 814.45(d) to discontinue individual publication of PMA approvals and denials in the Federal Register. Instead, the agency now posts this information on the Internet on FDA’s home page at http://www.fda.gov. FDA believes that this procedure expedites public notification of these actions because announcements can be placed on the Internet more quickly than they can be published in the Federal Register, and FDA believes that the Internet is accessible to more people than the Federal Register.” 72 Fed. Reg. pp. 3863-64. The regulations now provide that the FDA publish a quarterly list of available safety and effectiveness summaries of PMA approvals, with the public being directed to www.fda.gov/cdrh/pmapage.html for more detailed information.
16 As an example of an in-depth critique of methodology, we refer to CMS’ published national coverage determination for lumbar artificial disc replacement discussed in n.8, supra (though we do not rely on its findings). [We note that CMS must disclose the factors it considers in making NCDs by making guidance documents publicly available, which CMS does through the Internet. 42 U.S.C. § 1395y(l)(1); documents available at http://www.cms.hhs.gov/MedicareCoverageGuideDocs/] An NCD may entail consultation with outside technological or clinical experts, and a public comment period is provided following the Internet-based publication of an NCD draft decision. 42 U.S.C. § 1395y(l)(2)-(4).] When CMS set out to determine if the ProDisc was a reasonable and necessary treatment for Medicare patients with chronic low back pain caused by DDD, its first step was to assess the strength of published clinical studies by using methodological criteria that rate (1) the scientific validity of findings asserting a causal connection between treatments and outcomes, and (2) the absence of study biases. Appendix A: General Methodological Principles of Study Design, located at http://www.cms.hhs.gov/determinationprocess/downloads/id197d.pdf (last visited December 18, 2007). Techniques promoting the internal validity of a study include randomized allocation of patients to an intervention or control group; contemporaneous control groups rather than historical controls; prospective rather than retrospective studies; larger sample sizes; preventing patients and investigators from knowing which group they have been assigned to, especially when subjective outcomes such as pain are being measured; elimination of selection bias regarding eligible participants; elimination of detection bias in collecting data; avoidance of attrition bias (patients who do not complete the study); and elimination of co-interventions that may confound the study. Id.

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