The employer and insurer appeal from the compensation judge’s determination that the employee has been permanently and totally disabled since July 27, 2006, and her award to the employee of an additional 5% permanent partial disability of the body as a whole for the lumbar spine pursuant to Weber v. City of Inver Grove Heights, 461 N.W.2d 918, 43 W.C.D. 471 (Minn. 1990). We affirm in part, and vacate and modify in part.

Bill J. Clasen, the employee, began working as a carpet and floor installer in the early 1970s. On April 28, 1981, the employee sustained a low back injury while working for Rob’s Floor Service. He sought medical care at Unity Hospital for severe back pain and sciatic radiation down the left leg. A CT scan showed a herniated disc at L5-S1 with a free fragment extending into the left lateral recess displacing the left nerve root. The L3-4 and L4-5 discs appeared normal. Surgery was performed in May 1981, consisting of a partial laminectomy and removal of disc material at the L5-S1 disc space. In 1984, the employee was paid for a 15% permanent partial disability to the back.

The employee was off work for an extended period of time, receiving retraining in electronics, but did not find work in the field. Instead, in the late 1980s, the employee returned to carpet and floor installation work. He was self-employed until 2000 when he began working for Pro Floor, Inc., the employer.

On September 7, 2004, the employee was injured in a multiple car accident while driving to an installation job. The employee was seen in the emergency room at Woodwinds Health Center following the accident and was prescribed Vicodin for neck and low back pain. In late September 2004, the employee began treating with Dr. Peter Marshall at Riverside Occupational Medicine Clinic. Dr. Marshall diagnosed a neck strain/sprain and prescribed anti-inflammatory medication, a muscle relaxant, a TENS unit and physical therapy. The doctor released the employee to return to work, eight hours a day, with restrictions of no lifting over 20 pounds or over mid-chest level and a change of positions as needed.

The employee returned to work for the employer in a light-duty capacity. He was initially assigned service and repair work, but when this work aggravated his condition, was moved to lighter duty work in the warehouse tool room. In December 2004, Dr. Marshall, noting the employee’s limited progress, recommended shifting focus to a program of work hardening and conditioning along with appointment of a qualified rehabilitation counselor (QRC).

On March 8, 2005, a neurology evaluation was conducted by Dr. Vivian Fink. On examination, deep tendon reflexes were present and symmetrical in the knees and ankles, sensory findings were within normal bilaterally, gait was normal and toe-heel walk was normal. The doctor stated the employee’s condition was nonsurgical, and recommended ongoing physical therapy with heat, massage and TENS.

On April 11, 2005, the employee was moved to a temporary light-duty job in the employer’s clerical area. Dr. Marshall, on April 17, reviewed the employee’s diagnosis, treatment plan and permanent disability with the employee and his QRC. The doctor recommended no further medical treatment, but advised continuing home exercise, Tylenol, heat and TENS. Dr. Marshall assigned permanent eight-hour a day work restrictions, including no lifting over 30 pounds rarely, no lifting over 20 pounds on an occasional basis, no lifting over mid-chest, and minimize repetitive and frequent neck flexion and rotation. On May 4, 2005, the employee returned to Dr. Marshall reporting constant low back pain with left leg pain aggravated by his new job assignment. Physical therapy was prescribed. The employee completed twelve sessions, through July 7, 2005, with fair improvement.

In August 2005, the employee, dissatisfied with his progress, sought a second opinion from Dr. John Dowdle, an orthopedic surgeon. Dr. Dowdle noted a normal neurologic examination and diagnosed mechanical neck pain with degenerative disc disease at C6-7 and mechanical low back pain with degenerative lumbar discs. The employee returned to Dr. Dowdle on September 20, 2005, reporting more discomfort in his neck and back and that bending and activities increased his back pain. The doctor prescribed a Medrol Dosepak, ordered MRI scans of the neck and back, and took the employee off work until his return visit.

The September 29, 2005, lumbar scan showed chronic, multi-level lower lumbar disc degeneration, moderate chronic disc degeneration without stenosis or neural compression at L5-S1, and mild left facet joint degeneration at L4-5 with subluxation of L4 and L5. On October 12, based on the cervical scan showing moderate to severe right foraminal stenosis at C6-7, Dr. Dowdle ordered a discogram, continuing the employee off work until completion of the study. The cervical discogram was consistent with four-level degenerative disc disease, ruling out surgical intervention. At the follow-up visit on November 10, 2005, Dr. Dowdle recommended an active exercise program to decrease the employee’s pain and increase his functional abilities. The doctor continued the employee off work until completion of the exercise rehabilitation program.

The employee was evaluated by Dr. Thomas Kraemer at Physician’s Diagnostics & Rehabilitation (PDR) on December 29, 2005. Dr. Kraemer recommended an aggressive twelve week course of physical rehabilitation using MedX equipment for strengthening and conditioning. On March 30, 2006, Dr. Dowdle noted the employee had been involved in the program at PDR for just a short time and was making some progress.

The employee filed a claim petition in November 2005 alleging injuries to his neck and back as a result of the September 7, 2004, accident and seeking temporary total disability and medical benefits. A deposition was taken of Dr. Dowdle on May 17, 2006. The doctor testified that with the exercise program, the employee was doing better, was having less discomfort, had more function and was able to do more activity. Dr. Dowdle recommended a functional capacities evaluation (FCE) after completion of the MedX program, and testified he anticipated releasing the employee to return to work within the restrictions established by the FCE at that point.

A hearing was held before a compensation judge at the Office of Administrative Hearings on June 1, 2006. In a Findings and Order served and filed June 22, 2006, the judge found the employee sustained a compensable work injury to his neck and back on September 7, 2004, and was temporarily and totally disabled from and after September 20, 2005, through the date of the hearing. This decision was not appealed.

The employee was discharged from the MedX program on May 26, 2006. Dr. Kraemer stated the employee showed objective improvement in lumbar functional strength and cervical strength and rotation, but minimal subjective improvement in terms of daily pain. The doctor observed the employee continued to demonstrate loss of motion and muscle spasm in the cervical and lumbar spine. Dr. Kraemer further stated he agreed with Dr. Dowdle’s decision to keep the employee off work during the MedX program to minimize the impact of work activities, and agreed with the recommendation of an FCE to assess work ability in order to return to employee to some type of gainful employment.

The FCE was conducted over two and one-half days from June 27 to 29. The evaluator concluded the employee could not work full-time and could not return to flooring installation work, but could work four hours a day, five days a week, with restrictions of no prolonged static postures; no bending or stooping except on a seldom basis; limited squatting or crawling; minimal lifting; no grasping with his left hand and limited grasping with the right; and no overhead work.

Dr. Dowdle, the employee, and the employee’s QRC met on July 27, 2006, to review the FCE. Noting the employee’s condition progressively worsened over the course of the testing, Dr. Dowdle concluded the employee was not capable of sustained activities. Observing the employee was 62 years old and had few transferable job skills, Dr. Dowdle stated he did not believe the employee was capable of competitive employment and opined the employee was permanently and totally disabled. Dr. Dowdle assigned a 10% permanent partial disability rating under Minn. R. 5223.0390, subp. 3.C.(2),^[1] for the employee’s current condition, and stated the employee had reached maximum medical improvement (MMI) as of that date. Assuming conversion and apportionment of the employee’s prior 15% rating would result in no additional payment for the 2004 injury, Dr. Dowdle also provided a 5% “Weber” rating, explaining the rating equitably represented the employee’s additional functional impairment.

The employee filed a new claim petition in August 2006. The employee claimed permanent total disability effective October 30, 2006, or in the alternative, July 27, 2006, and sought additional permanency benefits. The employer and insurer denied the employee was permanently totally disabled, asserting the employee was able to work at least part-time, or, in the alternative, that the employee was permanently disabled as of September 20, 2005. The employer and insurer further argued that, under Minn. Stat. § 176.101, subd. 4a, after apportioning out the previously paid permanent partial disability to the back, no additional permanency was due. In a Findings and Order served and filed September 19, 2007, the compensation judge found that, based on the restrictions imposed on July 27, 2006, the employee was incapable of sustained gainful employment and was permanently and totally disabled as of that date. The judge additionally awarded an additional 5% whole body impairment of the lumbar spine as a result of the September 7, 2004, accident. The employer and insurer appeal.

On appeal, the employer and insurer do not dispute the employee is permanently and totally disabled. They contend, however, the compensation judge’s determination that the employee was permanently disabled commencing on July 27, 2006, is clearly erroneous and not supported by substantial evidence. The appellants assert the medical records show little change in the employee’s condition since Dr. Dowdle took him off work, note the employee never returned to work thereafter, and argue that, in retrospect, the employee’s last day of work, September 20, 2005, was the effective date of permanent total disability.

Law of the case. The employee argues the compensation judge’s prior, unappealed decision finding the employee temporarily and totally disabled from September 20, 2005, through June 1, 2006, is the law of the case and is not subject to collateral attack on appeal. “Law of the case” applies where an appellate court decides a legal question in a previous decision in the same matter. That rule of law is conclusive in subsequent proceedings in the court below. Collateral estoppel precludes relitigation of an issue explicitly put in issue and directly litigated and determined in a prior proceeding. See, e.g., Brezinka v. Bystrom Bros., Inc., 403 N.W.2d 841, 39 W.C.D. 880 (Minn. 1987); Moshier v. Park Masonry, 57 W.C.D. 54 (W.C.C.A. 1997); Lidtke v. Howard Lidtke Constr. Co., 56 W.C.D. 286 (W.C.C.A. 1996).

In this case, there is no prior appellate court decision establishing a rule of law. Moreover, the supreme court has held that a finding of temporary total disability may be superseded by a finding of permanent total disability where the temporary total benefits paid were, in reality and with the benefit of hindsight, payments for permanent total disability. Christensen v. Whirlpool, Inc., 41 W.C.D. 1047 (W.C.C.A. 1989)(citing Souden v. Hopkins Motor Sales, Inc., 289 Minn. 138, 182 N.W.2d 668, 25 W.C.D. 314 (1971)). The employee made no claim for permanent total disability until after the prior decision was rendered in this matter. Thus, the question presently before this court on appeal was not and could not have been litigated or determined previously. Accordingly, neither the law of the case nor collateral estoppel have any application here.

Substantial Evidence. This court has stated on many occasions that a finding of when an employee’s permanent total disability commenced requires resolution of a question of fact and, as with other questions of fact, the issue for this court is whether substantial evidence supports the compensation judge’s determination. See, e.g., Fields v. Paper & Graphics, 52 W.C.D. 545 (W.C.C.A. 1995); Christensen v. Whirlpool, Inc.., 41 W.C.D. 1047 (W.C.C.A. 1989); Fletcher v. Todd County, slip op. (W.C.C.A. Mar. 23, 2004). There is rarely a clear line of demarcation that establishes exactly when an employee became permanently totally disabled. Rather, the compensation judge must take into consideration all of the facts and circumstances relating to both the medical and vocational aspects of the matter. Lidtke v. Howard Lidtke Constr., slip op. (W.C.C.A. June 26, 1990).

In this case, Dr. Dowdle took the employee off work on September 20, 2005, until further diagnostic testing was completed. When it became apparent the employee was not a surgical candidate, Dr. Dowdle recommended an aggressive exercise program. The employee completed the program the end of May 2006. Both Dr. Dowdle and Dr. Kraemer agreed the employee made some progress and objective evidence of improvement was noted. The employee was provided with the services of a QRC, and it is clear that Dr. Dowdle, Dr. Kraemer and the QRC anticipated the employee would be released to return to work after completion of the MedX program followed by a functional capacities evaluation. It was not until after completion of the FCE that Dr. Dowdle concluded the employee was not capable of sustained activities and opined the employee was permanently and totally disabled. On these facts, while a different inference could have been drawn, the compensation judge’s determination that the employee was not permanently and totally disabled until July 27, 2006, was not unreasonable or unsupported by the evidence. Compare, e.g., Harrison v. Cleaning Concepts, Inc., 526 N.W.2d 46, 51 W.C.D. (Minn. 1994). We must, therefore, affirm.

The employer and insurer argue the compensation judge erroneously awarded an additional 5% permanent partial disability pursuant to Weber on the facts in this case. We agree.

In Weber, the supreme court recognized the permanency schedules could not cover every possible rateable disability. Accordingly, the court held that non-scheduled injuries resulting in functional impairment may not be excluded from coverage. Minn. Stat. § 176.105, subd. 1(c), essentially codifies Weber, providing “[i]f an injury for which there is objective medical evidence is not rated by the permanent partial disability schedule, the unrated injury must be assigned and compensated for at the rating for the most similar condition that is rated.” Statute and case law thus allow a rating for an injury not addressed in the permanent partial disability schedules. However, a Weber rating is not appropriate in cases where an employee’s impairment is included in the schedules. The employee’s condition in this case is specifically described and rated in the permanency schedules under Minn. R. 5223.0390, subp. 3.C.(2), as Dr. Dowdle recognized in assigning permanency under that rule. Accordingly, a supplemental rating under Weber is not permissible. See, e.g., Stenhammer v. Fleming Cos., 61 W.C.D. 751 (W.C.C.A. 2001); Finn v. Homecrest Indus., Inc., 61 W.C.D. 534 (W.C.C.A. 2001); Oakgrove v. MCTO, 61 W.C.D. 333 (W.C.C.A. 2001). We, therefore, vacate the compensation judge’s award of a 5% permanent partial disability under Weber.

We agree, however, with the compensation judge’s conclusion that the employee does have additional, compensable permanent impairment of the lumbar spine as a result of his September 7, 2004, injury. In Fleener v. CBM Indus., 564 N.W.2d 215, 217, 56 W.C.D. 495, 498-99 (Minn. 1997), the supreme court observed:

In 1981, the employee was paid for a 15% permanent partial disability to the back. His diagnosis was a herniated disc at L5-S1 with a free fragment extending into the left lateral recess displacing the left nerve root, treated by surgery consisting of a partial laminectomy and removal of disc material at the L5-S1 disc space.^[2] The employee returned to work as a carpet and floor installer in the late 1980s. He testified he was physically able to perform the work and did not have any significant difficulties with his back during that time. Dr. Dowdle noted the employee had not needed medical treatment for his back for 15 years. He observed that during this time, the employee was doing flooring work, heavy physical labor, and was quite functional doing his regular work activities without restrictions or limitations.

Following the 2004 injury, Dr. Dowdle diagnosed mechanical low back pain with multi-level degenerative disc disease. The MRI scan confirmed moderate disc degeneration without neural compression at L5-S1, and mild left facet joint degeneration at L4-5 with subluxation of L4 and L5. The doctor further observed the scan showed dehydration, consistent with disc degeneration, at every level of the lumbar spine. Based on persistent muscle tightness and loss of range of motion with multi-level degenerative changes, Dr. Dowdle assigned a 10% rating under Minn. R. 5223.0390, subp. 3.C.(2). The doctor stated the 2004 accident permanently aggravated the employee’s low back, indicating the pattern of pain and symptoms were different, and noting the employee had been able to work as a carpet and floor installer prior to the accident but had persistent problems and difficulties following the accident and was now unable to perform sustained activities or return to work.

This case involves two discrete injuries, separated by twenty-three years, involving different and separately rateable conditions.^[3] Under these facts, neither statutory nor equitable apportionment is applicable.^[4] We, therefore, modify the compensation judge’s decision, concluding the employee is entitled to a 10% permanent partial disability to the body as a whole as a result of the September 7, 2004, work injury.