S1 Radiculopathy Masquerading as Plantar Fasciitis: a Case Report

Plantar fasciitis (PF) is the most common cause of heel pain and is estimated to affect 10% of the general population during their lifetime.1 Over the past decade, PF accounted for 1 million patient visits per year to medical physicians in the United States.2 According to the clinical practice guidelines from the Orthopaedic Section of the American Physical Therapy Association,3 the diagnosis of PF is made using the following history and physical examination findings: plantar medial heel pain (most noticeable with initial steps after inactivity, but also worse following prolonged weight-bearing activities); heel pain precipitated by a recent increase in weight-bearing activity; pain with palpation of the proximal insertion of the plantar fascia at the medical calcaneal tubercle; limited active and passive ankle dorsiflexion range of movement; abnormal Foot Posture Index score; high body mass index in nonathletic individuals; positive windlass test; and negative tarsal tunnel tests.

The high prevalence of plantar fasciitis diagnoses suggests that the condition may be over diagnosed; moreover, “plantar fasciitis has become the umbrella term for many different causes of plantar heel pain”4 and there may be no gold standard to identify the condition.15 Nevertheless, most of time the diagnosis of PF is straightforward;5 however, in cases where pain localization is poor, differential diagnosis may include: tarsal tunnel syndrome, entrapment of the first branch of the lateral plantar nerve, subtalar arthritis, S1 nerve root impingement, central heel pain syndrome, fat pad atrophy, proximal plantar fibroma, fat pad contusion, calcaneal bone bruise, or calcaneal stress fractures.3,5-7 Diagnostic imaging can be used for PF; however, it usually isn’t necessary and rarely changes management. That is, although heel spurs on x-ray,8,9 thickened plantar fascia on ultrasound,10 and “hot” bone scan on the calcaneus are more common in patients with PF, many asymptomatic individuals can have the same imaging findings.

Notably, when a patient with a diagnosis of “plantar fasciitis” does not improve through conventional treatments, minimally improves with frequent relapses, or experiences plantar heel pain bilaterally, a central component should be considered.11-20 More specifically, S1 radiculopathy and sciatic nerve impingement are possible central and neurogenic causes of plantar heel pain that can mimic PF because the lumbosacral nerves (i.e. the tibial nerve) innervate the plantar aspect of the foot.17,18,21 There is certainly overlap between the clinical presentation of PF and S1 radiculopathy, as both are capable of generating plantar medial heel pain and tenderness to palpation in that region; in addition and notably, S1 radiculopathy can generate localized heel pain without being accompanied by the classical radicular nerve pain sensations that radiate down the posterior thigh and lower leg.11,12,15,17,21-23However, there is a paucity of research that has investigated specific management strategies in patients with underlying S1 radiculopathy that is masquerading as PF. Therefore, the purpose of this article is to present a single case report of a patient with bilateral plantar heel pain and to describe the interventions that were used to alleviate such.

CASE DESCRIPTION & INTERVENTION

A 54-year-old female with an 8-month history of plantar heel pain was referred to physical therapy by a podiatrist with a diagnosis of “bilateral plantar fasciitis”. The patient reported plantar medial heel pain that was worse on the left than the right. The medial calcaneal tubercles were tender during palpation and painful (8/10 on the NPRS) during weight-bearing activities. Notably, the patient also reported a long history of low back pain. The patient complained of discomfort and pain during posterior palpation over the L4-S1 region, reported increases in low back and heel pain with active lumbar flexion, and demonstrated an approximate 50% reduction in active range of motion during lumbar side bending, rotation and extension due to the onset of low back pain . The patient also presented with bilateral weakness of the hip abductors (3/5 MMT) and demonstrated a positive SLR test on the left with heel pain reproduction during sensitizing maneuvers. Her initial FAAM score revealed a 57% disability.

During the initial treatment, interventions included a supine sciatic nerve glide and dry needling with manual and electric stimulation to the lumbar paraspinals over the L2-S1 region. Ten 50-mm needles were placed bilaterally (5 on each side) one finger (i.e. P-A insertion angle with a depth of 30 mm) or two fingers (i.e. anteromedial and slightly caudal insertion angle with a depth of 40 mm) from each spinous process. The two most inferior needles were inserted at the midpoint between the medial aspect of the PSIS and midline down toward the S1 foramina (i.e. BL31) with the intent of perineural electrical stimulation targeting the S1 nerve roots.24-26 Following insertion, needles were manipulated bi-directionally to elicit a sensation of aching, tingling, deep pressure, heaviness or warmth.27,28 The needles were then left in situ for 15-20 mins with electric stimulation (ES-160 electrostimulator ITO co.) in pairs to all 10 needles using a low frequency (2 Hz), moderate pulse duration (250 microseconds), biphasic continuous waveform at an intensity described by the patient as “mild to moderate”.29

OUTCOME

Immediately following the first treatment session, the patient reported a significant reduction in heel pain and was able to perform barefoot weight-bearing activities for 3 minutes prior to the return of any heel pain. The patient attended a total of 6 physical therapy treatment sessions and received the same electrical dry needling intervention during the first 4 sessions.  By the third session, she reported a worst-pain score of 1/10, and at discharge (3 weeks after the initial evaluation), the patient reported a GROC score of +7 and a NPRS score of 0/10 for foot pain. At the 3-month follow up, the patient reported a full return to all weight-bearing activities without shoes including a triweekly Pilates class, as well as a significant decrease in low back pain. Her three-month GROC and NPRS scores remained +7 and 0/10, respectively, and her FAAM score improved to 10% disability.

CONCLUSION

To our knowledge, this is the first case report to describe the outcome of perineural and electric dry needling targeting the S1 nerve roots and lumbosacral paraspinals in a patient with an apparent case of S1 radiculopathy that was previously diagnosed by the podiatrist as bilateral “plantar fasciitis”.

AUTHORS

Stephanie M. Campbell, PT, DPT, Cert. DN, Cert. SMT, Dip. Osteopractic
Fellow-in-Training, AAMT Fellowship in Orthopaedic Manual Physical Therapy
Osteopractic Physical Therapist, Taylor Rehab, Mooresville, NC

Raymond Butts, PhD, DPT, MSc (NeuroSci), Dip. Osteopractic
Senior Faculty, AAMT Fellowship in Orthopaedic Manual Physical Therapy
Louisville, KY

James Dunning, PhD, DPT, MSc (Manip Ther), FAAOMPT, Dip. Osteopractic
Director, AAMT Fellowship in Orthopaedic Manual Physical Therapy
Montgomery, AL

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