Citation Nr: 21007611 Decision Date: 02/10/21 Archive Date: 02/10/21 DOCKET NO. 10-49 089 DATE: February 10, 2021 ORDER Entitlement to service connection for sleep apnea, to include as due to exposure to environmental hazards, a qualifying chronic disability under 38 C.F.R. § 3.317, or as secondary to a service-connected disability, is granted. Entitlement to service connection for bone condition, left leg, other than left knee disability, to include as secondary to service-connected external cutaneous nerve damage, left lower extremity associated with symptomatic scar, residual of left leg laceration injury, is denied. Entitlement to an initial compensable disability rating for external cutaneous nerve damage, left lower extremity associated with symptomatic scar, residual of left leg laceration injury, is denied. REMANDED Service connection for left knee disability, to include as secondary to service-connected degenerative joint disease, right knee, is remanded. Entitlement to service connection for rectal/colon polyp to include as due to exposure to environmental hazards or a qualifying chronic disability under 38 C.F.R. § 3.317, is remanded. Entitlement to a total disability rating based on individual unemployability due to service-connected disability (TDIU) is remanded. FINDINGS OF FACT 1. The Veteran’s sleep apnea began during active service. 2. The Veteran’s symptoms of left leg pain and weakness have been attributed to his service-connected symptomatic scar, residual of left leg laceration injury; external cutaneous nerve damage, left lower extremity; and left leg scar. 3. The Veteran’s external cutaneous nerve damage, left lower extremity, is manifest by no more than mild to moderate paralysis. CONCLUSIONS OF LAW 1. The criteria for service connection for sleep apnea, to include as due to exposure to environmental hazards, a qualifying chronic disability under 38 C.F.R. § 3.317, or as secondary to a service-connected disability are met. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.303. 2. The criteria for service connection for bone condition, left leg, other than left knee disability, to include as secondary to service-connected external cutaneous nerve damage, left lower extremity associated with symptomatic scar, residual of left leg laceration injury are not met. 38 U.S.C. §§ 1110, 5107; 38 C.F.R. §§ 3.102, 3.303. 3. The criteria for a compensable rating for external cutaneous nerve damage, left lower extremity, have not been met. 38 U.S.C. §§ 1155, 5107; 38 C.F.R. §§ 4.1, 4.3, 4.124a, Diagnostic Code (DC) 8529. REASONS AND BASES FOR FINDINGS AND CONCLUSIONS The Veteran served on active duty for training from May 12, 1988, to September 15, 1988, and on active duty from October 1990 to May 1991. These matters come before the Board of Veterans’ Appeals (Board) on appeal from multiple rating decisions. In December 2014, the Veteran withdrew his request for a Travel Board hearing. 38 C.F.R. § 20.704(e). In a February 2018 decision, the Board denied service connection for sleep apnea, to include as due to exposure to environmental hazards during Gulf War service or as secondary to a service-connected disability. The issue of entitlement to service connection for headaches, to include as due to exposure to environmental hazards during Gulf War service or as secondary to a service-connected disability was also denied. The Veteran appealed to the United States Court of Appeals for Veterans Claims (Court), and in an October 2019 memorandum decision, the Court vacated the Board’s decision as to the appealed issues and remanded the matter for further development and readjudication consistent with the memorandum decision. The issues were previously before the Board in August 2020 when they were remanded for further development. In the August 2020 decision, the Board found that the issue of TDIU had been raised by the record as part and parcel of the Veteran’s increased rating claim and the issue was added to the appeal. Rice v. Shinseki, 22 Vet. App. 447 (2009). Following the Board’s remand, the Veteran was granted service connection for chronic fatigue syndrome in an October 2020 rating decision. The Veteran’s disability of chronic fatigue syndrome was noted to include the symptoms of headaches, breathing problems, sleep disturbances, fatigue, constipation, and joint and muscle pain. As such, the Board finds that the issue of entitlement to service connection for headaches, to include as due to exposure to environmental hazards, a qualifying chronic disability under 38 C.F.R. § 3.317, has been granted in full and is no longer on appeal before the Board at this time. Service Connection Service connection may be granted for disability resulting from disease or injury incurred in or aggravated by active service. 38 U.S.C. §§ 1110, 1131, 5107; 38 C.F.R. § 3.303. The three-element test for service connection requires evidence of: (1) a current disability; (2) in-service incurrence or aggravation of a disease or injury; and (3) a causal relationship between the current disability and the in-service disease or injury. Shedden v. Principi, 381 F.3d 1163, 1166 -67 (Fed. Cir. 2004). 1. Entitlement to service connection for sleep apnea, to include as due to exposure to environmental hazards, a qualifying chronic disability under 38 C.F.R. § 3.317, or as secondary to a service-connected disability The Veteran contends that his sleep apnea had its onset in service and has continued since his time in service. He contends that his sleep apnea is due to exposure to environmental hazards during his Gulf War service or as secondary to a service-connected disability. In its October 2019 memorandum decision, the Court found that the Board erred when it failed to afford the Veteran the combat presumption under 38 U.S.C. § 1154 when denying service connection for sleep apnea on a direct basis in February 2018. The Court stated: “Remand is warranted for the Board to readjudicate the matters on appeal based on the appellant’s apparent status as a combat veteran. 38 U.S.C. § 1154.” Consequently, the Veteran is considered a combat veteran entitled to the combat presumption under 38 U.S.C. § 1154(b). The Court also concluded that the Board had erred when it found the VA medical opinions of record to be adequate because the VA examiners failed to consider that the Veteran’s “cluster of symptoms, including headaches, fatigue, and sleep disturbances, could warrant service connection for Gulf War Syndrome. See 38 C.F.R. § 3.317(2)(ii)(b)(3) (listing fatigue, headaches, and sleep disturbances as symptoms that can be manifestations of an undiagnosed illness).” Rather, all the Veteran’s symptoms of sleep disturbance were attributed to his sleep apnea, and the sleep apnea and headaches were considered individually. The Court stated that it “fails to understand how a Gulf War Veteran could not suffer from both sleep apnea and Gulf War Syndrome.” In August 2020, the Board remanded the claim in order to afford the Veteran a new VA examination, including an adequate Gulf War General Medical examination, for consideration of his symptoms individually as well as a cluster. The Board also directed the RO to schedule the Veteran for a Gulf War examination in order to determine if the Veteran’s reported symptoms of headaches, breathing problems, sleep disturbances, fatigue, constipation, as well as joint and muscle pain constituted a qualifying chronic disability under 38 C.F.R. § 3.317. The examiner was also directed to address the issue of whether a Gulf War Veteran could not suffer from both sleep apnea and Gulf War Syndrome. As noted, the Veteran is entitled to the combat presumption. When a Veteran has engaged in combat with the enemy, satisfactory lay or other evidence “shall be accepted as sufficient proof of service connection” for certain diseases or injuries, even if “there is no official record of such incurrence or aggravation in such service.” See 38 U.S.C. § 1154 (b). In Reeves v. Shinseki, 682 F.3d 988 (Fed. Cir. 2012), the claimant presented evidence, in the form of his own statements and statements of his fellow soldiers, that he suffered hearing loss while firing a mortar during the Second World War. Id. at 990. After a long procedural history before the Board and the Court, the Federal Circuit rejected the argument that the Board had no need to apply the combat presumption because the Board had agreed with the claimant that he suffered acoustic trauma in service. Rather, the Board was required to apply the section 1154(b) presumption to the separate question of whether he also suffered permanent hearing loss while on active duty. In short, although the record contained evidence of the cause of Reeves’ disability acoustic trauma from mortar blasts... he still had the right to invoke the section 1154(b) presumption in order to show that he incurred the disability itself while in service. Id. at 999 (emphasis in original). The Board must consider the Veteran’s combat experience in resolving the issue of service connection for sleep apnea. Reeves v. Shinseki, 682 F.3d 988, 999 (Fed. Cir. 2012). Under the analysis used in Reeves, the combat presumption of section 1154(b) applies not only to prove that the Veteran incurred sleep apnea during such service. Although medical evidence is generally necessary for a nexus to service, lay evidence can be sufficient to show continuity of symptoms after service, as a foundation for a nexus opinion, to link chronic in-service symptoms to the same diagnosed current disability, or as a substitute for a nexus. See Jandreau v. Nicholson, 492 F.3d 1372, 1377 (Fed. Cir. 2007); Layno v. Brown, 6 Vet. App. 465 (1994). When assessing the probability that the Veteran’s current sleep apnea is related to his service, the Board has considered the application of the combat presumption in Reeves and the Veteran’s competent statements suggesting that his sleep apnea began in service in the Gulf War and continued until diagnosis in May 2008. Taken together, these circumstances support a finding that the evidence is at least evenly balanced as to whether the Veteran incurred his current sleep apnea during active duty service. Accordingly, the Board finds that service connection for sleep apnea is warranted. See Jandreau v. Nicholson, 492 F.3d 1372, 1376-77 (Fed. Cir. 2007). 2. Entitlement to service connection for bone condition, left leg, other than left knee disability, to include as secondary to service-connected external cutaneous nerve damage, left lower extremity associated with symptomatic scar, residual of left leg laceration injury The Veteran contends that he suffers from a left leg disability, other than his left knee disability, as a result of his service. In the alternative, the Veteran contends that his left leg disability is secondary to his service-connected external cutaneous nerve damage in his left lower extremity. A June 2010 memorandum of formal finding stated that, after exhaustive efforts, the Veteran’s service treatment records obtained were incomplete. The Board notes that the Veteran submitted additional service treatment records on his own. Service treatment records show that in January 1991 the Veteran fell from the back of a two-and-a-half-ton truck in the company area while serving in Saudi Arabia. He sustained a laceration to the left lower leg, which required irrigation, debridement, and suturing followed by splinting with three days of hospitalization for elevation of the limb and administration of pain medication. The laceration was described as on the left medial leg “large 3-4 cm deep lacerated area” with the nerve-muscle-tendon intact. The Veteran stated in his February 2017 notice of disagreement: “I have X-ray evidence of joints with occasional incapacitating exacerbations;” “My military injury during the Gulf War reflects surgery on my left leg in 1990. All data within my current file;” and “I fell 15 feet from my fuel tanker during the Gulf War. I had surgery on my bone or leg. I have serious problems.” In an April 2010 letter, the Veteran’s wife stated that she remembered the Veteran reporting immediately after his in-service left leg injury that “if his right knee had not stopped the fall he could have possible [sic] lost his left leg.” He reported that he sustained bruising and swelling of his knee “from that day until now.” She stated that the Veteran “now walks with a limp.” During a March 2015 VA examination, the Veteran stated that when he slipped and fell, he hit his left leg and the right knee stopped it from being injured worse. He reported using knee braces and medications to help his knee pain. VA treatment records from December 2001 show that the Veteran complained of pain in his left leg. Private treatment records from January 2007 show that the Veteran reported physical pain in his legs for 16 years due to an injury. In the above-mentioned August 2020 remand, the Board directed the RO to schedule the Veteran for a VA examination to determine the nature and etiology of any identified bone condition of the left leg. The Veteran was provided with a VA knee and lower leg conditions examination in October 2020 where he reported “left knee pain and weakness.” The VA examiner noted that the Veteran has degenerative arthritis bilaterally, degenerative joint disease of the right knee, and a symptomatic scar in his left leg. The examiner opined that the Veteran’s left leg disability was less likely than not due to his service because “there are no other pathological conditions of the left leg,” other than his service-connected scar on his left leg and nerve damage in his left lower extremity. The examiner noted that the Veteran’s “decreased nerve sensation was noted on physical exam in the left lower extremity which is consistent with external cutaneous nerve damage.” The Board notes that the Veteran is already in receipt of service connection for symptomatic scar, residual of left leg laceration injury; external cutaneous nerve damage, left lower extremity; and left leg scar. As noted above, the October 2020 VA examiner found that the Veteran has no other pathological conditions of the left leg other than his service-connected scar and left leg nerve damage. As the Veteran’s symptoms of pain and weakness in his left leg have already been attributed to service-connected disabilities, service connection for a bone condition of the left leg is not warranted in this case. The Board has considered whether the Veteran’s symptoms may constitute a current disability to the extent it results in functional impairment of earning capacity. See Saunders v. Wilkie, 886 F.3d 1356 (Fed. Cir. 2018). However, as noted above, the Veteran’s symptoms of pain and weakness in his left leg have been attributed to his service-connected left leg scar and nerve damage of his left lower extremity, both of which are already service-connected. As the October 2020 VA examiner noted that there are no other pathological conditions of the left leg other than symptoms that have been attributed to service-connected disabilities, no further discussion is necessary regarding whether the Veteran’s symptoms result in functional impairment of earning capacity. In reaching this conclusion, the Board has considered the applicability of the benefit-of-the-doubt doctrine. However, as the preponderance of the evidence is against the claim, that doctrine is not applicable. See 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102; Gilbert v. Derwinski, 1 Vet. App. 49, 53-56 (1990). Increased Rating In general, disability evaluations are assigned by applying a schedule of ratings that represent, as far as can be determined, the average impairment of earning capacity. 38 U.S.C. § 1155; 38 C.F.R. § 4.1. Separate diagnostic codes identify the various disabilities and the criteria that must be met for specific ratings. The regulations require that, in evaluating a given disability, the disability be viewed in relation to its whole recorded history. 38 C.F.R. § 4.2; see also Schafrath v. Derwinski, 1 Vet. App. 589 (1991). The claimant bears the burden of presenting and supporting his/her claim for benefits. 38 U.S.C. § 5107(a); See Fagan v. Shinseki, 573 F.3d 1282 (Fed. Cir. 2009). The Board shall consider all information and lay and medical evidence that is of record. When there is an approximate balance of positive and negative evidence regarding any issue material to the determination of the matter, the Board shall give the benefit of the doubt to the claimant. 38 U.S.C. § 5107(b); 38 C.F.R. § 3.102. 3. Entitlement to an initial compensable disability rating for external cutaneous nerve damage, left lower extremity associated with symptomatic scar The Veteran contends that the external cutaneous nerve damage of his left lower extremity is more severe than what is represented by a noncompensable disability rating. Paralysis of the external cutaneous nerve of the thigh is evaluated in accordance with the criteria set forth in 38 C.F.R. § 4.124a, DC 8529. Neuritis and neuralgia of that group are evaluated under Diagnostic Codes 8629 and 8729. Under these criteria, mild to moderate paralysis is rated as noncompensable. Moderate to complete paralysis is rated as 10 percent disabling. 38 C.F.R. § 4.124a. The words “mild,” “moderate,” and “severe” as used in the various Diagnostic Codes are not defined in the Rating Schedule. Regulations provide that ratings for peripheral neurological disorders are to be assigned based the relative impairment of motor function, trophic changes, or sensory disturbance. 38 C.F.R. § 4.120. Consideration is also given for loss of reflexes, pain, and muscle atrophy. See 38 C.F.R. §§ 4.123, 4.124. The term “incomplete paralysis” indicates a degree of lost or impaired function substantially less than the type picture for complete paralysis given with each nerve, whether due to varied level of the nerve lesion or to partial regeneration. When the involvement is wholly sensory, the rating is for the mild, or at most, the moderate degree. The disability ratings for the peripheral nerves are for unilateral involvement; when bilateral, the ratings combine with application of the bilateral factor. 38 C.F.R. § 4.124a, Note at “Diseases of the Peripheral Nerves.” The Note to 38 C.F.R. § 4.124a establishes a maximum disability rating for conditions that are wholly sensory, as opposed to a minimum disability rating for conditions that are more than wholly sensory. See Miller v. Shulkin, 28 Vet. App. 376 (2017). The Veteran was provided with a VA peripheral nerves examination in July 2015 where he reported “numbness, tingling, and pain that shoots down the legs.” The VA examiner noted severe constant pain, intermittent pain, paresthesias and/or dysesthesias, and numbness in the left lower extremity. Muscle strength testing and reflex exams were normal and there was no muscle atrophy. The sensory exam indicated decreased sensation for the left lower leg/ankle. There were no trophic changes. The Veteran’s gait was normal. The examiner noted mild incomplete paralysis of the Veteran’s external cutaneous nerve of the left thigh. The Veteran was provided with another VA peripheral nerve conditions examination in November 2017 where the VA examiner reported that the Veteran did not have a peripheral nerve condition or peripheral neuropathy. The Veteran did not have any symptoms attributable to any peripheral nerve conditions. Muscle strength testing, reflex and sensory exams were all normal. There were no trophic changes, and the Veteran’s gait was normal. The Veteran was most recently provided with a VA peripheral nerve conditions examination in October 2020 where he reported worsening weakness. The VA examiner noted mild constant pain, moderate paresthesias and/or dysesthesias, and moderate numbness in the left lower extremity. Muscle strength testing showed active movement against some resistance with left knee extension. There was no muscle atrophy. The reflex exam was hypoactive in the left knee. The sensory exam showed decreased sensation in the left lower leg/ankle. There were no trophic changes and the Veteran’s gait was normal. The examiner noted moderate incomplete paralysis of the external cutaneous nerve of the left thigh. After a review of the evidence, the Board finds that due to the Veteran’s reports of numbness, tingling, and pain, his external cutaneous nerve damage in his left lower extremity results in moderate incomplete paralysis. As such, the Veteran is not entitled to a compensable rating under DC 8529. The Board acknowledges that the July 2015 VA examination noted severe symptoms of constant pain, intermittent pain, paresthesias and/or dysesthesias, and numbness in the left lower extremity. The VBA Adjudication Manual (M21-1) provides general guidelines for each level of incomplete paralysis of the upper and lower peripheral nerves. Mild incomplete paralysis can be described as a disability limited to sensory deficits that are lower graded, less persistent, or affecting a small area. A very minimal reflex or motor abnormality potentially could also be consistent with mild incomplete paralysis. Moderate incomplete paralysis is the maximum evaluation reserved for the most significant cases of sensory-only impairment. Symptoms will likely be described as significantly disabling. Combinations of significant sensory changes and reflex or motor changes of a lower degree or motor and/or reflex impairment such as weakness or diminished hyperactive reflexes (with or without sensory impairment) are graded as medically moderate. Severe incomplete paralysis includes motor and/or reflex impairment such as atrophy, weakness, or diminished hyperactive reflexes at a grade reflecting a very high level of limitation or disability. Trophic changes may be seen in severe longstanding neuropathy cases. See M21-1, Part III, Subpart iv, Chapter 4, Section N, Topic 4, Assigning Level of Incomplete Paralysis, Neuritis, or Neuralgia. The Board acknowledges that when relying on any M21-1 provision, the Board must independently review the matter the M21-1 addresses. If after such review, the Board chooses to rely on the M21-1 as a factor in its analysis or as the rule of decision, it must provide adequate reasons or bases for doing so. The Board may not simply rely on the nonbinding M21-1 position without analysis. Overton v. Wilkie, 30 Vet. App. 257 (2018). In this case, the Board finds that the Veteran’s symptoms do not rise to the level of severe to complete paralysis of the external cutaneous nerve of the thigh because the evidence of record does not show any atrophy, weakness, or diminished hyperactive reflexes resulting in a very high level of limitation or disability. The Veteran’s symptoms of constant pain, intermittent pain, paresthesias and/or dysesthesias, and numbness in the left lower extremity were considered by the July 2015 VA examiner, but were still found to result in mild incomplete paralysis of the Veteran’s external cutaneous nerve of the left thigh. Additionally, the Board notes that the July 2015 VA examination showed normal muscle strength testing, no atrophy, normal reflexes, and no trophic changes. Although the left lower leg/ankle was shown to have decreased results for sensation testing for light touch, sensation testing was not absent and the Board notes that this does not rise to a high level of limitation in order to warrant a compensable rating under Diagnostic Code 8529. Additionally, the November 2017 and October 2020 VA examinations did not indicate severe to complete paralysis. Both examinations showed no atrophy. Although the October 2020 VA examination showed decreased strength with knee extension showing active movement against some resistance and hypoactive reflexes in the left knee, the Veteran had joint movement and reflexes were still present. Such findings do not support a compensable rating under Diagnostic Code 8529. The Board has considered all other potentially applicable Diagnostic Codes, but there is no evidence showing that the Veteran has neurological impairment associated with any other peripheral nerves that have not already been service-connected. Therefore, a separate or higher rating under a different Diagnostic Code is not warranted. In conclusion, the Board finds that the preponderance of the evidence is against the Veteran’s claim for a compensable rating. In denying such a rating, the Board finds the benefit of the doubt doctrine is not applicable. 38 U.S.C. § 5107; 38 C.F.R. §§ 4.3, 4.7. REASONS FOR REMAND 1. Entitlement to service connection for left knee disability, to include as secondary to service-connected degenerative joint disease, right knee The Veteran contends that he suffers from a left knee disability as a result of his service. In the alternative, the Veteran contends that his left knee disability is secondary to his service-connected right knee disability. As noted above, service treatment records show that in January 1991 the Veteran fell from the back of a two-and-a-half-ton truck in the company area while serving in Saudi Arabia and sustained a laceration to his left lower leg. The Board notes that in an August 2015 decision, relying upon competent and credible lay evidence, the Board granted service connection for degenerative joint disease, right knee, finding that the symptomatology of the chronic condition of arthritis began during service and continued to manifest thereafter. An October 2015 referral to orthopedic surgery shows a diagnosis of posttraumatic osteoarthritis of both knees. October 2015 X-ray imaging revealed moderate osteoarthritis of the knees, right greater than left. The examiner for an October 2016 VA examination for knee and lower leg conditions recorded the diagnosis of left knee degenerative arthritis. In an April 2010 letter, the Veteran’s wife stated that she remembered the Veteran reporting immediately after his in-service left leg injury that “if his right knee had not stopped the fall he could have possible [sic] lost his left leg.” He reported that he sustained bruising and swelling of his knee “from that day until now.” She stated that the Veteran “now walks with a limp.” During a March 2015 VA examination, the Veteran stated that when he slipped and fell, he hit his left leg and the right knee stopped it from being injured worse. He reported using knee braces and medications to help his knee pain. VA medical records show that in November 2001, X-rays of the Veteran’s tibia and fibula were taken due to complaint of “left knee and tibia pain s/p open fracture ? ‘90, no recent trauma, sx gradually worse.” The impression was stated as: “No evidence of acute injury, destructive process, or other significant abnormality seen.” VA medical records show that in December 2001 the Veteran complained of left knee pain, which he rated as 10/10; he was issued a brace and medication. Records show that during a follow up evaluation the Veteran was wearing a left knee brace, and he reported that the medicine was working to control the pain. He reported being very busy at work delivering packages. The Veteran was provided with a VA knee and lower leg conditions examination in October 2016 where the VA examiner opined that the Veteran’s left knee disability was less likely than not caused by his service-connected right knee disability. It was explained that medical literature indicated that “the most likely cause of degenerative joint disease is older age or trauma to the specific joint.” It was stated that no objective evidence was found to support a causal relationship between the arthritis of the right and left knees. It was stated that an injury to one joint would not have a substantial impact on an opposite joint. In November 2017, the Veteran was afforded another VA knee and lower leg conditions examination, and the VA examiner opined that the Veteran’s left knee arthritis was less likely than not proximately due to the Veteran’s service-connected right knee disability because there was “no known medical evidence to support the conclusion that arthritis of one joint causes arthritis in the other.” It was stated that the Veteran’s arthritis was diagnosed in 2007, 16 years after his fall and that it was more likely to be the result of mere aging than “to a minor laceration in 1991.” In August 2020, the Board found the November 2017 medical opinion to be inadequate because the lay and medical evidence established that the Veteran’s left leg laceration required surgical care, hospitalization for three days, and splitting/casting for a significant period of time, such that it was more than a “minor laceration.” Second, an opinion was not provided as to service connection on a direct basis. In relying solely on a 2007 diagnosis of left knee arthritis to determine date of onset, the examiner failed to consider the lay evidence concerning the chronic and continuous nature of the Veteran’s symptoms prior to diagnosis. The Board noted that the lack of a complete medical record could not be used to establish that the Veteran did not complain of left knee pain after the accident. See Dalton v. Nicholson, 21 Vet. App. 23 (2007). Furthermore, although the Veteran was released from active duty in May 1991, military personnel records show that he did not retire from the Reserves until June 1996, which was only a few years prior to his initial contact with VA in 2000 when he clearly complained of left knee disability. The Board noted that the Veteran may have had an incentive not to complain about or seek treatment for left knee pain to protect his ability to continue to serve in the Reserves. As such, the Board remanded the issue in order to obtain a new VA examination to determine the nature and etiology of the Veteran’s left knee disability, to include whether the Veteran’s left knee disability was proximately due to or aggravated by a service-connected disability. In the remand instructions, the Board advised the VA examiner that the lack of contemporaneous service treatment records documenting any specific complaint as to the left knee during active service, alone, was not a sufficient rationale for a negative opinion. The examiner was directed to include a discussion of the January/February 2007 and October 2015 diagnoses of traumatic arthritis, the Veteran’s repeated reports of hitting both knees during the January 1991 fall, the reports of chronic and continuous left knee symptomatology starting with the Veteran’s first contact with VA, and the prescription and use of a left knee brace since December 2001. The Veteran was subsequently provided with a VA knee and lower leg conditions examination in October 2020 where he was found to have degenerative arthritis bilaterally. The VA examiner opined that the Veteran’s left knee disability was less likely than not due to his service. The examiner noted that the Veteran was treated for “a laceration on his left medial leg,” while in service, but “the record does not report knee pain as a complication of this. The examiner added that “developing arthritis (degenerative joint disease) in the left knee 16 years after separation is due to aging joints and unrelated to the 01/08/1991 injury.” She also opined that the Veteran’s left knee disability was less likely than not proximately due to his right knee disability because “arthritis in one joint does not cause arthritis in another joint.” The examiner noted that “a thorough review of medical literature failed to show such causal relationship,” and “it is not unusual for two joints to share properties in the same person, but one joint’s disease does not ‘spread’ to another or cause damage to it.” The examiner noted that “aging is one of the causes of osteoarthritis (degenerative arthritis/degenerative joint disease).” The examiner concluded that the Veteran’s left knee disability “is less likely than not related to the degenerative joint disease of the right knee, PTSD, symptomatic scar, residual of left leg laceration injury, external cutaneous nerve damage, left lower extremity, and left leg scar.” She added that “a nexus has not been established.” The examiner also found that the Veteran’s left knee disability was not aggravated by his service-connected disabilities because the Veteran reported to a “VA clinic on 07/21/2016 with complaint of worsening knee pain since starting his valet parking job and was requesting a work restriction note.” The examiner noted that “this indicate that Veteran’s knee condition was aggravated by his job as a valet attendant which requires prolonged standing and getting in and out of cars.” The examiner added that “there is no evidence that his left knee condition was aggravated by degenerative joint disease of right knee, PTSD, symptomatic scar, residual of left leg laceration injury, external cutaneous nerve damage, left lower extremity, and left leg scar.” The Board finds that an addendum medical opinion is required prior to adjudication of this issue because the October 2020 VA examiner based her negative nexus opinion on the lack of contemporaneous service treatment records documenting any specific complaint as to the left knee without addressing the Veteran’s lay statements regarding his in-service injury and his continuity of symptoms since then. It is not clear from the opinion whether the examiner found that the Veteran’s lay statements were inconsistent with medical science or if she concluded that medical treatment would have been necessary for this type of injury while in service. Additionally, the Board finds that the October 2020 secondary negative nexus opinion is inadequate because it is based on an insufficient rationale. Although the examiner explained that arthritis from one joint cannot spread to another when discussing whether the Veteran’s left knee disability is secondary to the Veteran’s right knee disability, she did not explain how the Veteran’s left knee disability is not proximately due to or aggravated beyond its natural progression by the Veteran’s other service-connected disabilities. Compliance with a remand is not discretionary, and failure to comply with the terms of a remand necessitates remand for corrective action. Stegall v. West, 11 Vet. App. 268 (1998). 2. Entitlement to service connection for rectal/colon polyp, to include as due to exposure to environmental hazards or a qualifying chronic disability under 38 C.F.R. § 3.317 The Veteran seeks service connection for rectal/colon poly (claimed as function gastrointestinal disorder), contending that his colon polyps were the result of his service in the Persian Gulf. Private treatment records from September 2015 shows that the Veteran had a 3-millimeter polyp removed from the recto-sigmoid colon, which was biopsied to rule out malignancy. The examination was noted as otherwise normal. In December 2016, the Veteran was afforded a VA examination for intestinal surgery, during which the surgical removal of the colon polyp was noted. It was noted that a positive FIT (fecal immunochemical test) screening in July 2015 resulted in the subsequent surgical intervention. In December 2016, he was also afforded a VA examination for intestinal conditions, during which a July 2015 diagnosis of colon polyps was noted. The Veteran reported that he had “been having issues over the last 2 years with having a large non-cancerous polyp removed.” He reported that he needed to go back to have another “small polyp” removed. He stated that he believed that his polyps were from his time in the Persian Gulf because he did not have any family members with a similar problem. He reported that he took Pepto Bismol for chronic constipation. The examiner indicated that the Veteran did not have episodes of bowel disturbance with abdominal distress or exacerbations or attacks of the intestinal condition. It was indicated that there had been no weight loss attributable to the condition or malnutrition, serious complications, or other general health effects attributable to the intestinal condition. A CBC (complete blood count) revealed hemoglobin of 14, hematocrit of 42.6, and platelets of 220. In December 2016, the Veteran was afforded a VA Gulf War General Medical examination, during which the examiner recorded the same details the Veteran reported during the examination for intestinal conditions. In the section for medical history, no answer was provided for digestive and abdominal wall/intestinal conditions. The response “No” was indicated for the question: “From the conditions identified and for which Questionnaires were completed, are there any diagnosed illnesses for which no etiology was established.” It was noted that the Veteran’s service treatment records were silent for diagnosis, treatment, or complaints of constipation. It was opined that “due to lack of compelling medical evidence it is less likely that the Veteran has an ongoing” issue with chronic constipation that is associated with his time in the Persian Gulf. It was stated that a review of the medical literature showed that “colon polyps are a common condition that can develop in anyone among the general public.” It was also stated that the medical literature did not support a positive causation between having colon polyps and serving in the Persian Gulf. It was concluded: “therefore, it is less likely than not that the Veteran has colon polyps as a result of, that occurred in, or because of exposure to environmental substances during his Gulf War service.” In August 2020, the Board found that a new VA examination was required to determine the nature and etiology of the Veteran’s rectal/colon polyp and constipation because the VA did not fulfill its duty to assist by not obtaining private treatment records regarding the Veteran’s colon polyps, and as these pertinent medical records were not available to the VA examiners, the examination reports were not probative. The Board advised the VA examiner that the lack of contemporaneous service treatment records documenting complaints of or treatment for gastrointestinal issues during active service, alone, is an insufficient rationale for a negative opinion. The Veteran was subsequently provided with a VA Gulf War medical examination in September 2020 where a VA examiner opined that the Veteran’s symptoms of headaches, breathing problems, sleep disturbances, fatigue, constipation, and joint and muscle pain collectively are “indicative of an un-diagnosed illness.” The Board notes that the Veteran was granted service connection for chronic fatigue syndrome based on this opinion in an October 2020 rating decision. The Veteran was provided with a VA intestinal conditions examination in October 2020 where the he reported that “he had stomach pain during service and was treated with OTC medications.” The Veteran was noted to have a diagnosis of status-post rectal and colon polyp. The VA examiner opined that the Veteran’s colon polyps were less likely than not due to his service. The examiner noted that “constipation is not a symptom of colorectal polyp.” She added that “there is no evidence that Veteran developed symptoms of colorectal polyps (colon and rectal polyps) during service.” The examiner noted that “according to Mayo clinic (2020), symptoms of rectal and colon polyps are rectal bleeding, change in stool color, change in bowel habits, pain, and iron deficiency anemia.” The examiner added that “while it is plausible that Veteran had constipation during and after service, this does not represent a change in bowel habit.” She noted that “this is because constipation can be caused by diet or be a symptom of other conditions such as irritable syndrome.” The examiner also found that a nexus had not been established for the Veteran’s colon polyps and his service, to include exposure to environmental toxins while serving in Southwest Asia. The Board finds that the October 2020 negative nexus opinion is inadequate as it relies on the lack of contemporaneous service treatment records documenting complaints of or treatment for gastrointestinal issues during active service and does not address the Veteran’s lay statements of having stomach pain in service. Although the VA examiner noted that pain is a symptom of colon polyps, she did not explain whether the Veteran’s lay statements regarding stomach pain in service could have been a symptom of colon polyps. Compliance with a remand is not discretionary, and failure to comply with the terms of a remand necessitates remand for corrective action. Stegall v. West, 11 Vet. App. 268 (1998). Additionally, the Board notes that the VA examiner did not provide an adequate rationale as to whether the Veteran’s colon polyps are due to his exposure to environmental toxins while serving in the Southwest Asia theater. The examiner merely stated that a nexus had not been established but did not provide a supporting rationale. Upon remand, the addendum opinion must address whether the Veteran’s colon polyps are due to his exposure to environmental toxins while serving in the Southwest Asia theater. 3. Entitlement to a TDIU The Veteran contends that he is unable to obtain substantially gainful employment as a result of his service-connected disabilities. The Veteran’s claim of entitlement to TDIU is inextricably intertwined with the issue being remanded in this appeal. See Harris v. Derwinski, 1 Vet. App. 180, 183 (1991). As such, the issue will be remanded for further development. Upon remand, the Veteran should be provided with another opportunity to complete and submit a VA Form 21-8940, the TDIU application form. The matters are REMANDED for the following action: 1. Provide the Veteran with a VA Form 21-8940, Veteran’s Application for Increased Compensation Based on Unemployability, and advise him to complete and return the form to support his claim for a TDIU. 2. Arrange for an appropriate health care provider to review the Veteran’s claims file and provide an opinion as to the following: a) Is it at least as likely as not (50 percent probability or greater) that the Veteran’s left knee disability had its onset in service or is otherwise etiologically related to any in-service disease, injury, or event in service, to include the January 1991 fall from a truck that resulted in his service-connected symptomatic scar, residual of left leg laceration injury? b) Is it at least as likely as not (50 percent probability or greater) that the Veteran’s left knee disability is (1) proximately due to or (2) aggravated beyond its natural progression by a service-connected disability, to include his right knee disability? The examiner should opine on whether the Veteran’s statements regarding ongoing symptoms are credible in light of the assembled evidence in this case, to include the medical principles describing onset and progress of the disease, the specific findings in the record, and your professional judgment. The examiner is advised that the Veteran is competent to report symptoms, treatment, and injuries, and that his reports must be considered in formulating the requested opinion. However, if there is a medical reason to doubt its veracity, the examiner should explain why the Veteran’s statements or recollection are inconsistent with the evidence in this case, medical principles relating to the onset and progress of the disease, the specific findings in the record, and/or your professional judgment. The examiner should indicate what types of symptoms would have manifested by the type of left knee injury at issue. The examiner is advised that the lack of contemporaneous service treatment records documenting any specific complaint as to the left leg or knee during active service, alone, is an insufficient rationale for a negative opinion. A fully articulated medical rationale for any opinion expressed must be set forth in the medical report. The examiner should discuss the particulars of this Veteran’s medical history and the relevant medical science as applicable to this case, which may reasonably explain the medical guidance in the study of this case. 3. Arrange for an appropriate health care provider to review the Veteran’s claims file and provide an opinion as to the following: a) Is it at least as likely as not (50 percent probability or greater) that the Veteran’s rectal/colon polyps had its onset in service or is otherwise etiologically related to any in-service disease, injury, or event in service, to include exposure to environmental toxins while serving in the Southwest Asia theater? The examiner is advised that the Veteran is competent to report symptoms, treatment, and injuries, and that his reports must be considered in formulating the requested opinion. However, if there is a medical reason to doubt its veracity, the examiner should explain why the Veteran’s statements or recollection are inconsistent with the evidence in this case, medical principles relating to the onset and progress of the disease, the specific findings in the record, and/or your professional judgment. The examiner is advised that the lack of contemporaneous service treatment records documenting any specific complaint as to rectal/colon polyps during active service, alone, is an insufficient rationale for a negative opinion. A fully articulated medical rationale for any opinion expressed must be set forth in the medical report. The examiner should discuss the particulars of this Veteran’s medical history and the relevant medical science as applicable to this case, which may reasonably explain the medical guidance in the study of this case. M. Donohue Veterans Law Judge Board of Veterans’ Appeals Attorney for the Board S. Morrad, Counsel The Board’s decision in this case is binding only with respect to the instant matter decided. This decision is not precedential and does not establish VA policies or interpretations of general applicability. 38 C.F.R. § 20.1303.