GERALD D. SIMONSON, Employee/Cross-Appellant, v. ZUPANICH BROS. and EBI COS., Employer-Insurer/Cross-Appellants, and ZUPANICH BROS. and SENTRY INS. CO., Employer-Insurer, and ZUPANICH BROS. and AMERICAN FAMILY INS. CO., Employer-Insurer/Appellants, and NORTHERN MINN.-WISC. RETAIL FOOD HEALTH & WELFARE FUND, Intervenor, and SPECIAL COMPENSATION FUND.
WORKERS= COMPENSATION COURT OF APPEALS
JANUARY 27, 2000
PERMANENT TOTAL DISABILITY - SUBSTANTIAL EVIDENCE. Substantial evidence, including the employee=s testimony and various medical and vocational opinions, support the compensation judge=s findings that the employee has been permanently and totally disabled since August 23, 1997 and that the employee=s low back injury is a substantial contributing cause of his permanent total disability.
APPORTIONMENT - PERMANENT TOTAL DISABILITY. Substantial evidence does not support the compensation judge=s determination attributing the employee=s permanent total disability solely to the employee=s August 1992 low back injury. However, as the nature and extent of any restrictions and permanent disability as a result of the employee=s right shoulder injury remained unresolved at the time of hearing, a determination on the facts as they existed at the time of the hearing would not be appropriate.
PERMANENT PARTIAL DISABILITY - LUMBAR SPINE. Substantial evidence, including the opinions of two examining physicians, supports the award of a 23 percent permanent partial disability for multiple level stenosis in the lumbar spine.
GILLETTE INJURY - DATE OF INJURY. Substantial evidence supports the compensation judge=s determination that the employee=s three Gillette injuries culminated in disability in 1997 and 1998 while EBI Companies was on the risk.
APPORTIONMENT - GILLETTE INJURY. Substantial evidence supports the compensation judge=s refusal to apportion liability for the employee=s Gillette injuries to other insurers where all of the injuries culminated while EBI Companies was on the risk.
CAUSATION - SUBSTANTIAL EVIDENCE. Substantial evidence supports the compensation judge=s determination that the employee failed to prove that his cervical spine degenerative disc disease, first diagnosed in December 1998, was work-related.
Affirmed in part and reversed in part.
Determined by: Johnson, J., Wilson, J., and Wheeler, C.J.
Compensation Judge: Gregory A. Bonovetz
THOMAS L. JOHNSON, Judge
Zupanich Brothers and American Family Insurance Company appeal the compensation judge=s finding that the employee has been permanently and totally disabled since August 23, 1997 and the finding that the employee=s permanent and total disability resulted solely from his admitted August 24, 1992 lumbar spine injury. The employer and American Family further appeal the award of 23 percent permanent partial disability benefits secondary to the lumbar spine injury. The employer and EBI Companies appeal the compensation judge=s finding that the employee sustained Gillette injuries in the nature of bilateral carpal tunnel syndrome and a right shoulder injury that culminated during EBI=s coverage of the employer. They further appeal the compensation judge=s denial of apportionment of liability among the insurers for the Gillette injuries. Finally, the employee appeals the compensation judge=s finding that the employee did not sustain a personal injury to his cervical spine arising out of his employment. We affirm in part and reverse in part.
Gerald Simonson, the employee, worked as a meat cutter for approximately 45 years starting in 1955. (T. 62.) In 1963 or 1964, Zupanich Brothers, the employer, purchased the IGA store at which the employee was then working. The employee continued to work at the store for the employer. On August 24, 1992, the employee sustained a personal injury to his low back when he slipped and fell while exiting a cooler. (T. 77.) On that date, the employee earned a weekly wage of $579.60. From at least August 24, 1992 through July 8, 1995, the employer was insured for workers= compensation liability by American Family Insurance Company. The employer and American Family admitted liability for the employee=s personal injury.
On September 16, 1992, the employee saw Dr. Davis at the Duluth Clinic complaining of right hip pain radiating into his leg. Dr. Davis diagnosed right hip pain of unknown etiology and ordered an MRI scan which showed moderate spinal stenosis at L4-5 and lesser spinal stenosis at L3-4 without evidence for disc herniation or protrusion. (Pet. Ex. A-B1.) Dr. Davis referred the employee to Dr. Hindle whom he saw on October 14, 1992. The employee complained of bilateral hip and right leg discomfort aggravated by twisting or lifting and stated he had been having difficulty performing his job over the last year because of the hip and leg symptoms. Dr. Hindle diagnosed lumbosacral strain with probable right sacroiliac dysfunction and prescribed physical therapy. On December 29, 1992, the employee saw Dr. Donnelly, a neurosurgeon, at the request of Dr. Hindle. Dr. Donnelly diagnosed nerve root entrapment at L3-4 and L4-5 and a central and lateral recess stenosis. By report dated May 11, 1993, Dr. Donnelly rated a 23 percent whole body disability, stated the employee would be able to resume his former employment temporarily and opined the employee had reached maximum medical improvement. (Pet. Ex. A-B4.)
On August 2, 1993, the employee was examined by Dr. Robert Leslie at the request of the employer and American Family. The doctor diagnosed spinal stenosis at L3-4 and L4-5 secondary to congenital narrowing of the spinal canal. Dr. Leslie opined the employee sustained a moderate permanent aggravation of a pre-existing condition as a result of his fall on August 24, 1992, rated a 19 percent whole body disability and opined the employee had reached maximum medical improvement. Dr. Leslie restricted the employee to no lifting over 75 pounds and no excessive bending. (Pet. Ex. A-M1.) The employer and American Family paid the employee the 19 percent permanent disability rated by Dr. Leslie.
Between 1955 and the early 1990s, the employee=s job as a butcher required him to carry heavy pieces of meat from a delivery vehicle to the store=s cooler. The meat often weighed from 150 to 200 pounds and the employee carried it primarily on his right shoulder. The employee did this twice a week for approximately 30 to 35 years. (Finding No. 12; T. 65.) By the mid 1980s or early 1990s, the meat was packed in boxes which weighed from 50 to 90 pounds. The employee also carried these boxes from the delivery vehicle to the cooler on his right shoulder approximately twice a week. (Finding No. 13; T. 66-67.) Between 1955 and 1997, the employee also carried heavy pieces of meat from the cooler to his butcher block where he would cut and wrap meat. (Finding Nos. 14-17; T. 66-70.) The employee=s duties as a butcher required extensive use of both his right and left hands. The employee typically spent five and a half to six hours a day cutting meat with his right arm and used both hands to wrap meat. (Findings 15, 16; T. 148-149.)
The employee testified that he had no low back problems before August 24, 1992 and was physically able to perform all his job duties. (T. 77-78.) Since his back injury, the employee has never been free of pain in his back or right leg. (Finding 19.) The employee testified his back condition progressively worsened from 1992 until he quit working in August 1997. During those years, the employee continued to perform the duties of his job as a meat cutter, occasionally exceeding the weight restrictions placed upon him by his doctors. Although a co-employee assisted the employee by carrying boxes of meat, the employee continued to perform physically taxing duties. By the summer of 1997, the employee=s legs became numb after working a half hour and he would occasionally trip and drag his right leg. (T. 82-86; Findings 24, 27.) By the end of the summer of 1997, the employee testified AI was reaching the end of the rope . . .@ and felt he could not continue working. (T. 87.)
In the summer of 1995, the employee also began to experience an aching in his right arm from the shoulder down to his wrist. (T. 106-107.) The employee testified he told Bernard, one of his bosses, that he was having trouble with his arm. (T. 132.) The employee modified his work activities by decreasing his lifting because of his right shoulder problem. The employee stated Athe kid [Brandon] did more of the work for me.@ If Brandon was unavailable, the employee asked other co-employees to help him. (T. 158.) The employee did not, however, miss any time from work due to his right shoulder problems. (T. 109-110.) The problems progressed and by late 1995, the employee was having problems holding onto a knife. (T. 108-109.) The employee attributed this problem to the tingling and numbness he felt in his right hand. (T. 112.) Several months later, the employee began to experience pain in his left wrist and numbness in his left thumb. This problem remained constant during the remainder of his employment. (T. 127-128.)
On March 25, 1996, the employee saw Dr. Mark Monson at the Duluth Clinic complaining of an onset of right arm pain running from his shoulder to his wrist with numbness and tingling in the right hand. Dr. Monson diagnosed carpal tunnel syndrome and prescribed a wrist splint. (Pet. Ex. A-B1.) An EMG was equivocal. (Pet. Ex. A-B14.) On June 26, 1996, the employee saw Dr. Peterson at the Community Health Center. The employee complained of right arm pain from his hand to his shoulder, numbness and tingling in the right hand and left arm symptoms with lifting or exertion. The doctor diagnosed possible carpal tunnel, epicondylitis or rotator cuff symptoms in the right arm and shoulder and possible atypical angina symptoms. On July 31, 1996, the employee was seen by Dr. W.F. Schnell who diagnosed rotator cuff tendinitis and injected the subacromial space with Lidocaine. The employee returned to see Dr. Schnell on February 26, 1997 with continuing complaints of right shoulder symptoms. The doctor diagnosed back pain with paresthesias and weakness in the right leg with positive EMG findings due to spinal stenosis and degenerative disc disease, and work-aggravated rotator cuff tendinitis and possible over-use nerve entrapment syndrome of the right arm. On April 23, 1997, Dr. Schnell recommended continued conservative care, a second EMG of the right arm and an MRI scan of the right shoulder. (Pet. Ex. A-I1.) The employee returned to see Dr. Monson on June 25, 1997, who diagnosed right shoulder tendinitis and carpal tunnel syndrome. An EMG on July 9, 1997 showed mild right symptomatic carpal tunnel syndrome, asymptomatic right tardy ulnar neuropathy and early left asymptomatic carpal tunnel syndrome. (Pet. Ex. A-B13.) Following the EMG, Dr. Monson referred the employee to Dr. Bradley C. Edgerton, an orthopedic surgeon who saw the employee on August 1, 1997. The doctor diagnosed right shoulder rotator cuff tendinitis and recommended a shoulder arthroscopy and acromioplasty with rotator cuff repair, if needed. The doctor recommended the employee=s carpal tunnel syndrome be reevaluated after the shoulder surgery. (Pet. Ex. A-B1.)
The employee began his annual three-week vacation on August 23, 1997. He took vacation at that time in anticipation of his upcoming right shoulder surgery. (T. 105) Prior thereto, the employee missed no time from work because of any right arm problems. (T. 109-110.) However, by the end of the summer of 1997, the employee testified he was Areaching the end of the rope@ because of his low back problems and did not feel he could continue working indefinitely. (T. 87.) The employee opined that notwithstanding his right shoulder surgeries and problems, his low back problems would have prevented returning to work for the employer as a butcher. (T. 141.) The employee has not returned to any employment since August 23, 1997.
On September 15, 1997, Dr. Edgerton performed an arthroscopy of the employee=s right shoulder with repair of the superior labrum, open acromioplasty and distal clavicle excision. (Pet. Ex. A-J2.) Dr. Edgerton prescribed physical therapy and kept the employee off work. On December 1, 1997, Dr. Monson recommended the employee discuss carpal tunnel surgery with Dr. Edgerton. (Pet. Ex. A-B1.) On December 10, 1997, Dr. Edgerton performed a right carpal tunnel release. A left carpal tunnel release was performed on February 10, 1998. (Pet. Ex. A-J2-3.)
The employee saw Dr. Robert F. Donley, a neurosurgeon, on March 12, 1998 on referral from Dr. Monson. The doctor noted the March 1998 MRI scan showed mild progression of spinal stenosis at L3-4 and L4-5 compared to the 1992 MRI study. Dr. Donley did not recommend surgery unless the employee became incapacitated.
The employee returned to see Dr. Edgerton on May 18, 1998, with complaints of continued right shoulder pain and paresthesias in the right hand. On April 29, 1999, the employee saw Dr. Jeffrey Klassen, an orthopedic surgeon, for an evaluation of the employee=s right shoulder and arm complaints. The doctor diagnosed probable recurrent right rotator cuff tear and probable recurrent median neuropathy. (Pet. Ex. A-B1.) An arthrogram of the right shoulder on May 10, 1999, showed a complete tear of the supraspinatus tendon. An MRI scan of the right wrist on the same date showed an incomplete carpal tunnel release or refibrosis in the same area. (Pet. Ex. B-B18.) On May 14, 1999, Dr. Klassen performed a revision right shoulder acromioplasty and revision rotator cuff repair. (Pet. Ex. A-J4.)
In February 1998, the employee filed a claim petition seeking benefits due to the 1992 low back injury and alleged Gillette injuries to his arms and right shoulder culminating on July 1, 1996. The employee sought temporary total disability benefits from August 23, 1997 and continuing, an undetermined amount of permanent partial disability benefits and medical expenses. In May 1998, American Family Insurance Group requested a temporary order for payment of temporary total disability benefits, medical expenses and rehabilitation benefits. A temporary order was filed on May 11, 1998. On May 29, 1998, American Family filed a Petition for Contribution against Sentry Insurance Company seeking reimbursement of all or a portion of the benefits paid under the temporary order. Sentry denied liability and alleged the employee=s Gillette injuries culminated on September 15, 1997 during the coverage of EBI. The employee later amended his claim to include a claim for permanent total disability benefits commencing August 23, 1997, 10 percent permanency for a cervical injury and 23 percent permanency for the low back injury. (T. 7-9.)
Dr. John Dowdle examined the employee on April 24, 1998 at the request of American Family Insurance Company. He diagnosed multi-level lumbar degenerative disc disease with mechanical low back pain, spinal stenosis at L3-4 and L4-5, impingement syndrome of the right shoulder with a good result following surgery and bilateral carpal tunnel syndrome with a good post-surgical response. Dr. Dowdle opined the employee=s injury of August 24, 1992 aggravated his underlying degenerative disc disease. The doctor also opined the employee sustained Gillette-type injuries in the nature of bilateral carpal tunnel syndrome and a right shoulder injury culminating in September or October 1995. Dr. Dowdle opined the employee was capable of working in a job which did not involve repetitive heavy lifting and allowed freedom of movement. He limited the employee to 30 pounds lifting and no repetitive bending, and related these restrictions to both the low back and right shoulder conditions. Dr. Dowdle rated an 18 percent permanent disability for the low back condition under Minn. R. 5223.0070, subp. 1.C.(2). (Pet. Ex. A-L1.)
On May 19, 1998, the employee was examined by Dr. Jack Drogt at the request of Sentry Insurance Company. The doctor diagnosed mechanical low back pain, degenerative disc disease and spinal stenosis; right shoulder pain with internal derangement of the glenohumeral joint, supraspinatus tendinosis, acromoclavicular-joint arthrosis and subacromial bursitis; and bilateral carpal tunnel syndrome. Dr. Drogt opined the employee=s work from July 9, 1995 to July 8, 1996 was not a substantial contributing cause of the right shoulder or bilateral carpal tunnel injuries. Rather, the doctor opined the employee=s work activities prior to July 9, 1995 were the principle cause of the right shoulder and bilateral carpal tunnel injuries. The doctor assigned a 30 pound lifting and carrying restriction with no frequent bending, stooping or flexing of the low back. With respect to the right shoulder, the doctor limited the employee to 30 pounds of lifting and carrying and no overhead lifting or use of his arms in a repetitive nature. Dr. Drogt opined the employee sustained no additional permanent disability of the lumbar spine beyond the 19 percent paid by American Family. (Pet. Ex. A-K.)
On December 8, 1998, the employee was examined by Dr. Keith Bengston at the Mayo Clinic. The employee complained of right arm problems from the right shoulder to the wrist with paresthesia in the right hand. (Pet. Ex. A-N2.) The doctor ordered an EMG which showed chronic right C6 radiculopathy. (Pet. Ex. A-N3.) On December 21, 1998, the employee underwent a cervical MRI scan at the Duluth Clinic which showed degenerative changes particularly at the C5-6 level, including flattening and a 30 percent narrowing of the spinal cord and narrowing of the C5-6 neural foramen. (Pet. Ex. A-B17.) The employee returned to see Dr. Bengston on December 23, 1998, who reviewed the MRI study and felt the images were suboptimal. The doctor diagnosed right C6 radiculopathy secondary to foraminal stenosis and right shoulder pain, rotator cuff tear. (Pet. Ex. A-N4.) Dr. Bengston referred the employee to Dr. Meier, a neurosurgeon at the Mayo Clinic, who concluded the employee might be suffering from a cervical radiculopathy and referred the employee to Dr. Krueger, a neurologist. On examination, Dr. Krueger noted significant limitation of motion of the right shoulder, negative Phalen=s and Tinel=s sign with modest reduction of cervical range of motion. Dr. Meier concluded the employee=s right shoulder pain resulted from a shoulder derangement and advised the employee to continue with orthopedic care. The doctor recommended no further treatment for the carpal tunnel syndrome. Finally, the doctor stated he could not exclude some cervical radiculopathy although he found little evidence of such condition on his examination or the EMG. The doctor diagnosed cervical spondylosis. (Pet. Ex. A-N6.)
On December 21, 1998, Dr. Duane F. Person examined the employee at the request of his attorney. The doctor obtained a history from the employee, reviewed medical records and examined the employee. Dr. Person diagnosed multi-level degenerative cervical disc disease, multi-level stenosis and degenerative arthritis of the lumbar spine, chronic impingement syndrome of the right shoulder and bilateral carpal tunnel syndrome. The doctor opined the cervical spine condition, right shoulder condition and bilateral carpal tunnel syndrome resulted from repetitive trauma incurred at the employee=s employment and culminated in disability in September 1997 when the employee quit working. The doctor rated a 10 percent disability secondary to the cervical spine injury, 23 percent secondary to the lumbar spine injury, 14 percent permanent disability for the right shoulder condition and three percent permanent partial disability for the right carpal tunnel syndrome. Dr. Person opined the employee is permanently and totally disabled and stated the employee=s back condition, by itself, would cause such permanent and total disability. (Pet. Ex. A-A1.)
On March 1, 1999, the employee met with David Berdahl for a vocational evaluation at the request of American Family. At that time, the employee was 61 years old and resided in Silver Bay, Minnesota. The employee stated he graduated from Cook High School in 1955 and had no subsequent formal education or training since then. The employee has worked as a meat cutter since 1955 and was involved with his wife in a real estate business. Mr. Berdahl concluded the employee has transferrable skills in customer service related jobs and the cognitive capability to learn and perform jobs in areas where he does not have work experience or demonstrated transferrable skills. Specifically, Mr. Berdahl opined the employee could work as a hotel/motel desk clerk which paid approximately $7.00 an hour. Another employment option would be customer service/order taking which paid up to $12.45 an hour. Mr. Berdahl opined other employment options for the employee include work as a cashier, retail clerk, real estate sales, and possibly manufacturing. Mr. Berdahl did a labor market survey and concluded there were jobs available within the employee=s restrictions in his geographical area. Given a reasonable and diligent job search by the employee, Mr. Berdahl concluded the employee was employable. (T. 239-240.) Mr. Berdahl acknowledged the employee had restrictions and limitations on his vocational capabilities based upon his back injury and his right shoulder injury. Mr. Berdahl opined the right shoulder injury was the more significant disability and apportioned 75 percent of the employee=s vocational loss to the shoulder and 25 percent to the back. (Am. Fam. Ex. 4.)
On April 9, 1999, Dr. Larry Stern examined the employee at the request of EBI Companies. The doctor diagnosed right shoulder impingement syndrome with SLAP lesion and partial rotator cuff tear, right and left carpal tunnel syndrome and cervical spondylosis. The doctor related the employee=s current low back condition and need for medical care to his 1992 work injury. Dr. Stern opined the employee sustained Gillette injuries to his left and right wrist and right shoulder which culminated on June 26, 1996. The doctor felt the employee could work but only with significant restrictions including no use of the right arm at or above shoulder level and no use of the right hand for repetitive motions. Finally, Dr. Stern concluded the findings related to the employee=s cervical spine were age-related and opined the employee sustained no work-related cervical injury. (Pet. Ex. A-O1.)
On May 17, 1999, Jack H. Casper performed a vocational evaluation of the employee at the request of his attorney. Mr. Casper obtained an employment history, reviewed the medical records and the report of Mr. Berdahl. Mr. Casper concluded the employee had no transferrable skills. He opined the employee=s job opportunities were limited within the Silver Bay/Two Harbors, Minnesota, labor market. (T. 182.) Based on his restrictions, he concluded the employee would be categorized in the Asedentary category of work on a one-hand basis.@ The employee=s restrictions preclude a return to work as a meat cutter. (T. 185.) Given the employee=s age, his injury, his transferrable skills and the local labor market, Mr. Casper opined a job search was futile. (T. 187.) Finally, Mr. Casper concluded that due to either the back injury or the right upper extremity condition, the employee is totally vocationally disabled. (Pet. Ex. B.)
The case came on for hearing before a compensation judge at the Office of Administrative Hearings on May 26, 1999. In a Findings and Order served and filed August 25, 1999, the compensation judge found the employee was permanently and totally disabled effective August 23, 1997, and found the 1992 injury was the sole cause of the employee=s total disability. The compensation judge further found the employee sustained a 23 percent permanent partial disability secondary to his low back injury. American Family appeals these findings. The compensation judge further found the employee suffered a Gillette injury to his right shoulder and Gillette injuries of bilateral carpal tunnel syndrome, culminating in 1997, during the coverage of EBI. EBI was ordered to pay the employee for a three percent permanent partial disability for the right carpal tunnel syndrome and pay all medical expenses for the care and treatment of the right shoulder and bilateral carpal tunnel syndrome. EBI Companies appeals these findings and orders. Finally, the compensation judge denied the employee=s claim of a Gillette injury and denied his claim for permanent partial disability benefits relating to the cervical spine. The employee appeals this finding.
STANDARD OF REVIEW
On appeal, the Workers' Compensation Court of Appeals must determine whether "the findings of fact and order [are] clearly erroneous and unsupported by substantial evidence in view of the entire record as submitted." Minn. Stat. ' 176.421, subd. 1 (1992). Substantial evidence supports the findings if, in the context of the entire record, "they are supported by evidence that a reasonable mind might accept as adequate." Hengemuhle v. Long Prairie Jaycees, 358 N.W.2d 54, 59, 37 W.C.D. 235, 239 (Minn. 1984). Where evidence conflicts or more than one inference may reasonably be drawn from the evidence, the findings are to be affirmed. Id. at 60, 37 W.C.D. at 240. Similarly, findings of fact should not be disturbed, even though the reviewing court might disagree with them, "unless they are clearly erroneous in the sense that they are manifestly contrary to the weight of the evidence or not reasonably supported by the evidence as a whole.@ Northern States Power Co. v. Lyon Food Prods., Inc., 304 Minn. 196, 201, 229 N.W.2d 521, 524 (1975).
1. Permanent Total Disability.
American Family appeals the compensation judge=s finding that the employee was permanently and totally disabled as of August 23, 1997. It contends this finding is premature because as of the date of hearing, May 26, 1999, the employee was still recovering from his May 14, 1999 right shoulder surgery. American Family cites Dr. Edgerton=s December 19, 1997 report which states Ait is too early to say if he will be totally disabled on a permanent basis from work.@ (Pet Ex. A-B2.) The appellant also cites Mr. Berdahl=s opinion that it was premature to decide whether the employee is permanently and totally disabled because the effects of the shoulder injury are unknown. (T. 243-244.) Accordingly, the appellant asserts the compensation judge=s award of permanent total disability benefits should be reversed.
"Permanent total disability is primarily dependent on an employee's vocational potential, rather than his physical condition." Thompson v. Layne of Minn., 50 W.C.D. 84, 100 (W.C.C.A. 1994), summarily aff'd (Minn. Jan. 19, 1994); see McClish v. Pan-O-Gold Baking Co., 336 N.W.2d 538, 542, 36 W.C.D. 133, 139 (Minn. 1983) (concept of total disability depends on employee's ability to find and hold job, not on his or her physical condition). "[A] person is totally disabled if his physical condition, in combination with his age, training, and experience, and the type of work available in his community, causes him to be unable to secure anything more than sporadic employment resulting in an insubstantial income." Schulte v. C.H. Peterson Constr. Co., 278 Minn. 79, 83, 153 N.W.2d 130, 133-34, 24 W.C.D. 290, 295 (1967).
The employee graduated from high school in the mid 1950s and has had no additional education or training. His sole work experience has been as a butcher for only two employers. He was 61 years of age at the time of the hearing and lived in Silver Bay, Minnesota. Mr. Casper concluded the employee had no transferrable skills and a very limited job market given his age and total vocational profile. Mr. Casper reviewed the doctors= restrictions which he concluded placed the employee in a sedentary category of work on a one-hand basis and would preclude the employee from returning to work as a meat cutter. Finally, Mr. Casper opined that due to either the back condition or the right upper extremity condition, the employee is totally vocationally disabled. Dr. Person stated that considering the employee=s age, his job as a meat cutter, his transferrable skills, his education and the local economy, the employee was permanently and totally disabled. Dr. Person further opined the employee=s back problem by itself would cause permanent and total disability. Finally, Dr. Person rated a total of 14 percent permanent partial disability secondary to the employee=s right shoulder condition. Although their examinations predated the May 1999 right shoulder surgery, both Dr. Dowdle and Dr. Drogt placed significant restrictions on the employee=s work activities. Substantial evidence of record supports the compensation judge=s conclusion that the employee is permanently and totally disabled.
In an unappealed finding, the compensation judge found that as of the date of hearing, the employee continued to recover from the effects of the May 14, 1999 right shoulder surgery. (Finding 59.) That fact does not, however, mandate reversal of the finding that the employee is permanently and totally disabled. Rather, the question is whether the evidence supports a conclusion that the low back injury is a substantial and contributing cause of the employee=s total disability. If so, American Family is liable to pay permanent total benefits to the employee whether or not American Family may have a claim for apportionment against a later insurer. Marsolek v. Miller Waste Mills, 244 Minn. 55, 69 N.W.2d 617, 18 W.C.D. 244 (1955). An employee need not prove that the employment was the sole cause, only a substantial contributing cause of the disability for which benefits are sought. Swanson v. Medtronics, Inc., 443 N.W.2d 534, 536, 42 W.C.D. 91, 94-95 (Minn. 1989).
The employee testified that his low back problems limited his ability to work. He opined that by August 1997 his low back problems had progressed to the point that he felt he could not continue working indefinitely. There is medical testimony that the employee=s vocational abilities are significantly limited due to the low back injury. Dr. Person and Mr. Casper opined the employee=s low back injury alone was sufficient to cause permanent and total disability. The court considered the opinion of Mr. Berdahl and found it not persuasive. We note that it is the compensation judge's responsibility, as trier of fact, to resolve conflicts in expert testimony. Nord v. City of Cook, 360 N.W.2d 337, 342, 37 W.C.D. 364, 372 (Minn. 1985). The testimony of the employee together with the medical and vocational opinions adequately support a conclusion that the low back injury is a substantial contributing cause of the employee=s permanent total disability. Order No. 1 is, therefore, affirmed.
2. Apportionment of Permanent Total Disability Benefits.
The compensation judge found that Asince his cessation of work on August 23, 1997 the employee, solely as a result of the low back injury of August 1992, has been and continues to be permanently totally disabled.@ (Finding 46.) Accordingly, the compensation judge ordered the employer and American Family to pay permanent total disability benefits to the employee from and after August 23, 1997. American Family contends this finding and order are unsupported by the evidence and are legally erroneous. The appellant contends that liability for permanent total disability benefits should be apportioned between the 1992 low back injury and subsequent Gillette injuries.
AIn Minnesota, common law principles of equitable apportionment have long been applied to permit apportionment between insurance carriers when two or more successive injuries combine to produce the final disability.@ Silva v. Maplewood Care Center, 582 N.W.2d 566, 58 W.C.D. 386 (Minn. 1998). Equitable apportionment is based on the principle that each liable employer or insurer should be responsible for its proportional share of the employee=s disability. Goetz v. Bulk Commodity Carriers, 303 Minn. 197, 226 N.W.2d 888, 27 W.C.D. 797 (1975). The liability of an employer or insurer for contribution is, however, dependent on a determination that the employee sustained a compensable injury with that employer or insurer and that the injury is a substantial contributing cause of the employee=s current disability. Haverland v. Twin City Milk Producers Ass=n, 273 Minn. 481, 142 N.W.2d 274, 23 W.C.D. 764 (1966). See also, Peterson v. O.R. Anderberg Constr., 586 N.W.2d 69, 58 W.C.D. 595 (Minn. 1998).
Since the 1992 low back injury is a substantial contributing cause of the employee=s permanent and total disability, the compensation judge properly ordered American Family to pay benefits to the employee. We do not, however, find substantial evidentiary support for the compensation judge=s finding that the 1992 injury was the sole cause of such permanent and total disability.
Dr. Person=s December 21, 1998 report states: AYou asked my opinion as to whether or not his back problem by itself would cause permanent and total disability, and my opinion is that it would.@ The doctor did not opine, however, that the right shoulder injury and/or the bilateral carpal tunnel syndrome were not substantial contributing causes to the employee=s permanent and total disability. Although not at issue here, Dr. Person did rate a total of 14 percent permanent disability secondary to the employee=s right shoulder injury. Neither did Mr. Casper testify that the right shoulder injury or bilateral carpal tunnel syndrome were not substantial contributing causes of the employee=s permanent and total disability. Rather, Mr. Casper stated: AMy opinion is that due to either the back condition or the right upper extremity condition he is totally vocationally disabled.@ (T. 187.) We find no medical or vocational support for the finding that the 1992 injury was the sole cause of the employee=s total disability. We therefore reverse that portion of Finding 36 which attributes the employee=s permanent and total disability solely to the August 1992 personal injury.
We take no position on whether the employee=s right shoulder injury or bilateral carpal tunnel syndrome substantially contributes to his permanent and total disability. The employee underwent a second operation on his right shoulder on May 14, 1999 and was still recuperating from that procedure on the date of hearing. No party had the opportunity to have the employee reevaluated, medically or vocationally, following the second surgery. The nature and extent of any restrictions and permanent disability secondary to the right shoulder injury remained unresolved. In view of the present status of the record, the court concludes it is not appropriate to remand the case to the compensation judge to decide the issue of whether American Family is entitled to contribution from a subsequent insurer. Rather, American Family may file a new petition for contribution, as appropriate.
3. Permanent Partial Disability Benefits - Lumbar Spine.
The compensation judge found the employee sustained a 23 percent permanent partial disability (18% + 5%)under Minn. R. 5223.0070, subp. 1.C.(2) secondary to his 1992 low back injury. American Family contends the employee has only an 18 percent permanent disability under subp. 1.C.(2) as opined by Dr. Dowdle. Alternatively, the appellant argues the employee has a 19 percent permanent disability as rated by Dr. Leslie: 14 percent under subp. 1.C.(1) plus 5 percent for a second vertebral level. (Pet. Ex. A-M1.) The appellant argues there is no evidence that the employee has severe spinal stenosis at multiple levels so the 23 percent rating is improper and must be reversed.
Minn. R. 5223.0070, subp. 1.C. (1992) provides two ratings for spinal stenosis:
(1) mild symptoms such as occasional back pain with athletic activities or repetitive bending or lifting, light pain with radicular symptoms, one vertebral level and no surgery, 14 percent; or
(2) severe spinal stenosis with bilateral leg pain requiring decompressive laminectomy, single vertebral level, with or without surgery (if multiple vertebral levels, add five percent per vertebral level), 18 percent.
The October 25, 1992 MRI scan showed moderate spinal stenosis at L3-4 and severe spinal stenosis at L4-5. (Pet. Ex. A-F2.) A second MRI scan on March 2, 1998 showed mild spinal stenosis at L2-3, mild to moderate spinal stenosis at L3-4 and moderate to severe spinal stenosis at L4-5. (Pet. Ex. A-B8.) The MRI scans clearly document spinal stenosis at multiple levels but severe spinal stenosis at only one level. Thus, neither part (1) or (2) of the rule for spinal stenosis fits exactly in this case. The employee has severe rather than mild stenosis at L4-5 with bilateral leg pain. Subpart 1.C.(1) is, therefore, inapplicable and the L4-5 stenosis is rated at 18 percent under subpart 1.C.(2). This 18 percent rating does not, however, compensate the employee for the spinal stenosis at L2-3 and L3-4. Both Dr. Donnelly and Dr. Person gave a 23 percent permanent disability under subpart 1.C.(2). The compensation judge adopted their opinions. We conclude a 23 percent rating fairly depicts the employee=s disability, and the compensation judge=s finding is affirmed.
4. Date of Gillette Injuries.
The compensation judge found the employee sustained Gillette-type personal injuries to his right shoulder and right and left arms and wrists arising out of his employment with Zupanich Brothers, and found the ongoing, minute trauma continued with the last exposure in August 1997. (Finding Nos. 53-56.) The compensation judge further found the right shoulder condition became disabling on September 15, 1997, the date of the employee=s right shoulder surgery, (Finding No. 50); the employee=s right carpal tunnel syndrome became disabling on December 10, 1997, the date of the right carpal tunnel release, (Finding No. 51) and the left carpal tunnel syndrome became disabling on February 10, 1998, the date of the left carpal tunnel release. (Finding 52.) Finally, the compensation judge found that EBI was the insurer on the risk at the time of disablement due to the three Gillette injuries. (Finding 57.) EBI, as cross-appellant, appeals each of these findings and argues the three Gillette injuries culminated prior to its coverage of the employer commencing on July 10, 1996.
As a general rule, Ainjuries resulting from repeated trauma or aggravations of a pre-existing condition result in a compensable personal injury when their cumulative effect is sufficiently serious to disable the employee from further work.@ Carlson v. Flour City Brush Co., 305 N.W.2d 347, 350, 33 W.C.D. 594, 598 (Minn. 1981). It is not, however, mandatory that an employee be totally disabled from all work activity or suffer a wage loss in order to determine that a Gillette injury has occurred. Johnson v. Lakeland Bean Co., 39 W.C.D. 884 (W.C.C.A. 1987). In Schnurrer v. Hoerner-Waldorf, 345 N.W.2d 230, 36 W.C.D. 504 (Minn. 1984) the supreme court held that the factfinder may look to other Aascertainable events@ in determining the date of a Gillette injury. The date on which minute trauma culminates in a Gillette-type injury is not so much a medical question as a question of ultimate fact for the compensation judge. Id.
EBI contends there are numerous ascertainable events which occurred prior to July 10, 1996. For example, the employee developed chronic symptoms in his right shoulder and right and left hand; the employee told his supervisor, Bernard, he was having trouble with his arm; the employee modified his work activities by decreasing his lifting because of his right shoulder problem; Dr. Monson diagnosed carpal tunnel syndrome and prescribed a wrist splint; Dr. Peterson diagnosed carpal tunnel syndrome and epicondylitis or rotator cuff symptoms in the right shoulder. These ascertainable events, EBI contends, mandate a finding that the Gillette injuries occurred prior to July 9, 1996. We disagree.
The employee worked his regular job from July 10, 1996 until August 23, 1997. He missed no time from work and suffered no wage loss due to the right shoulder condition or bilateral carpal tunnel syndrome during this time. These conditions did not cause the employee to suffer a wage loss until August 1997. Granted, there is evidence which might support a finding that the Gillette injuries to the employee=s right shoulder and right hand and wrist culminated prior to July 10, 1996. A compensation judge is not, however, required to fix the date of a Gillette injury on the date of the earliest ascertainable event. Rather, the date of a Gillette injury should be determined based on all of the evidence bearing on the issue. Schnurrer, 345 N.W.2d at 233; 36 W.C.D. at 509. The employee continued to suffer repetitive minute trauma from July 10, 1996 through August 23, 1997. He was first off work due to the effects of his Gillette injuries after August 23, 1997. We conclude substantial evidence supports the compensation judge=s finding that the employee=s three Gillette injuries culminated in disability in 1997 and 1998.
5. Apportionment of Gillette Injuries.
The compensation judge found the employee=s work duties through August 23, 1997, caused repetitive, minute trauma which caused Gillette injuries to the employee=s right shoulder and right and left hands and wrists. The last substantial exposure to such ongoing trauma ended in August 1997. Since EBI was the insurer on the risk on the date of the employee=s last employment, the compensation judge ordered EBI to pay the employee for a three percent permanent partial disability for the right carpal tunnel syndrome and ordered EBI to reimburse American Family and the intervenor for medical expenses for care and treatment of the employee=s right shoulder condition and bilateral carpal tunnel syndrome. On appeal, EBI contends the compensation judge erred by not apportioning liability for the Gillette injuries among American Family, Sentry and EBI.
As a general rule, apportionment of a Gillette injury is appropriate Aonly in those rare cases in which substantial and almost uncontrovered medical testimony will permit a precise allocation of responsibility between or among different employers or insurers for the employee=s disability.@ Michaels v. American Hoist & Derrick, 269 N.W.2d 57, 31 W.C.D. 55 (Minn. 1978). EBI contends the only apportionment opinion is that of Dr. Drogt who opined the employee=s work as a meat cutter over 35 years caused his right shoulder and carpal tunnel injuries. The doctor apportioned 80 percent of the liability for the injuries to the employee=s work prior to July 1995, 10 percent to the period from July 1995 to July 1996 and 10 percent to the period after July 1996. Dr. Drogt further opined, however, that the one year of work exposure from July 9, 1995 to July 8, 1996 was not a substantial contributing cause of either the right shoulder or bilateral carpal tunnel injuries. (Pet. Ex. A-K1.) This report EBI asserts constitutes uncontroverted medical testimony that the compensation judge was bound to accept. Accordingly, EBI contends the compensation judge=s failure to apportion liability for the Gillette injuries is legally erroneous. We are not persuaded.
Equitable apportionment is not purely a medical question but is ultimately a question of fact for the compensation judge which does not necessarily require choosing between conflicting medical apportionment opinions. Ringena v. Ramsey Action Programs, 40 W.C.D. 880, 883 (W.C.C.A. 1987), summarily aff'd (Minn. Mar. 28, 1988); "[T]here is a difference between disregarding unopposed medical opinion and rejecting it on the basis of other evidence." Clark v. Archer Daniels Midland, slip op. at 6 (W.C.C.A. Feb. 14, 1994). In making factual determinations, a compensation judge is not necessarily bound by medical opinion. Tuomela v. Reserve Mining Co., 299 Minn. 203, 204, 216 N.W.2d 638, 639, 27 W.C.D. 312, 313 (1974) (per curiam).
The compensation judge acknowledged that only Dr. Drogt apportioned liability for the Gillette injuries. The judge, however, noted that Dr. Drogt=s opinion was not uncontroverted, found it speculative, and declined to adopt his opinion. Although Dr. Drogt apportioned 10 percent liability to Sentry, he also opined the employee=s work activities during Sentry=s one year period of coverage were not a substantial contributing cause of the employee=s Gillette injuries. The doctor also stated the employee=s work activities during EBI=s 13 months of coverage were a contributing cause of the employee=s Gillette injuries. Dr. Drogt does not explain his reasons for these seemingly inconsistent opinions. The compensation judge was not bound to accept Dr. Drogt=s opinion. We, accordingly, affirm the compensation judge=s refusal to apportion liability.
6. Cervical Spine Injury.
The employee alleged a Gillette-type personal injury to his cervical spine culminating in disability in August 1997. He claimed a 10 percent permanent partial disability resulting from that injury based on the rating of Dr. Person. (Pet. Ex. A-A1.) The compensation judge found the employee did not sustain an injury to his cervical spine arising out of his employment and denied the employee=s claim for benefits. The employee appeals contending this finding is unsupported by substantial evidence and is clearly erroneous. The employee further argues the compensation judge failed to consider all of the evidence on the issue and asks this court to reverse the compensation judge=s finding and denial of benefits. We decline to do so.
The cervical MRI scan obtained on December 21, 1998 showed bulging discs at C4-5, C5-6 and C6-7, most prominent at C5-6. (Pet. Ex. A-N4.) Dr. Larry Stern concluded these changes to the employee=s cervical spine were age related and opined the employee did not sustain a work-related injury to his cervical spine. Although the compensation judge did not specifically reference Dr. Stern=s opinion, the compensation judge did find the preponderance of the evidence did not establish that the employee sustained a Gillette injury to his cervical spine. Dr. Stern=s report constitutes substantial evidence supporting that finding, and the compensation judge=s denial of benefits must, therefore, be affirmed.
 See Minn. R. 5223.0070, subp. 1.C.(2).
 References are to unappealed findings from the compensation judge=s findings and order.
 Sentry insured the employer from July 9, 1995 to July 9, 1996.
 EBI Companies insured the employer from July 10, 1996 through the employee=s last day of employment on August 23, 1997.
 The employee made no claim at the hearing for permanent partial disability benefits secondary to the right shoulder injury. The employee stated such a claim was premature in view of the May 14, 1999 surgery. (T. 9.)