Differential diagnosis and conservative management of thoracic intervertebral disc and rib conditions: A case report with 5-month follow up

Sargent E1,2, Brismée JM2,3, Apte G2,3

1 Doctor of Physical Therapy Program, University of Vermont, Burlington, Vermont, USA.

2 International Academy of Orthopedic Medicine – United States, Tucson, Arizona, USA.

3 Center for Rehabilitation Research, Texas Tech University Health Sciences Center, Lubbock, Texas, USA.

Author contact info:

Address: 306F Rowell Bldg, University of Vermont, Burlington, VT 05405

E-mail: elizabeth.sargent@med.uvm.edu

ABSTRACT

A 37-year-old male machine operator presented with acute thoracic spine and left middle rib pain following a rotatory mechanism of injury at work. Following clinical examination, the physical therapist identified the thoracic intervertebral disc (IVD) as the primary source of the patient’s pain given severe pain provocation with thoracic rotation and positive dural tension signs. The patient responded well to thoracic IVD decompression, IVD hydration management and direct treatment to the left 8th rib costochondral junction with full resolution of thoracic spine pain after 4 physical therapy visits. The patient was able to return to work and his pre-injury activities without restriction at the end of his physical therapy plan of care.

Key words: Thoracic intervertebral disc, rib, manual therapy, intervertebral disc hydration, physical therapy

INTRODUCTION

The thoracic spine and ribs are often overlooked during musculoskeletal examination given the relatively higher frequency of cervical and lumbar spine pain complaints.1 In fact, incidence of intervertebral disc (IVD) herniation, once thought to be rare, is being recognized more frequently leading to increased clinical awareness.2 The unique anatomical and biomechanical features of the thoracic spine and ribs make for an interesting clinical examination and differential diagnosis. Recent trends in physical therapy literature have de-emphasized the value of identifying the potential tissue responsible for the patient’s pain complaint due to lack of evidence supporting the identification of a pathoanatomical structure, particularly in cases of spinal pain.3 Historically, however, orthopedic manual physical therapy (OMPT) practice considers best evidence, integrating research and sound clinical reasoning in the examination and management of neuromusculoskeletal problems.4

The purpose of this case report is to (1) demonstrate the utility of a systematic examination of the thoracic spine and ribs for prioritizing intervention strategies, and (2) describe a successful course of treatment that included manual therapy and home program recommendations following an acute thoracic IVD lesion.

CASE DESCRIPTION

The patient, a 37-year-old male heavy machine operator, presented to physical therapy (PT) with left anterolateral trunk pain following an injury at work 6 days prior to his initial evaluation. He reported pulling with maximum effort on a wrench while working on a 400-ton hydraulic press and felt a pop in his trunk. He attempted to continue working and was unable due to pain in his midback and left sided ribs. He was seen by primary care for radiographs, which revealed no acute, displaced rib fractures. The primary care provider referred the patient to PT with the diagnosis of rib sprain. Upon initial evaluation, he reported a constant dull aching pressure in the left anterolateral ribs that became sharp with movement. He rated his pain on the Numeric Pain Rating Scale (NPRS) as 3/10 at best and 6/10 at worst. Aggravating factors were coughing, deep breathing, lying supine and in left side lying.  He reported difficulty turning in bed and demonstrated pain behaviors such as grimacing when transferring on and off the treatment table during the initial examination. The patient described a secondary pain between his scapulae characterized as a deep fatigue. His medical history included L5-S1 discectomy in 1998 complicated by a dural leak requiring a second surgery. Otherwise, the patient was healthy and fit, reporting regular exercise 5-7 days/week.

EXAMINATION

Prior to testing, visual patient observation revealed guarded posture with rounded shoulders and decreased lumbar lordosis. Swelling over the left 8th rib costochondral junction was visible and palpable. The cervical spine was screened to rule out cervical spine involvement. No limitations were found and no pain was provoked with cervical spine examination. Thoracic spine motion was moderately limited in all directions. The patient reported mild pain with thoracic flexion and cervical flexion testing was positive for reproduction of left sided rib pain. He reported moderate pain with thoracic side bending, left more than right and severe pain with thoracic rotation, left more than right. Active thoracic rotation motion to the left was the most painful test. Resisted thoracic isometrics were strong and painless with the exception of mild pain during resisted side bending bilaterally. Slump testing was positive bilaterally with concordant sign in the left anterolateral 8th rib, which decreased with left ankle plantarflexion. Patient reported hypersensitivity to light touch with palpation along the 8th rib and exquisite pain to palpation at the costochondral junction. Pain was not reproduced with rib springing. Posteroanterior spring testing to the spinous processes of the thoracic spine was not performed due to the patient’s unwillingness to lie prone secondary to pain. Lower extremity sensation and deep tendon reflexes were intact and symmetrical. The Modified Oswestry Low Back Pain Disability Index (MODI) score was 24% out of 100%, where 100% indicates total disability.

CLINICAL IMPRESSION

Following the clinical examination and review of diagnostic imaging it was determined that the patient demonstrated characteristics consistent with acute thoracic IVD pain based on the patient report of most pain with thoracic rotation5,9 and concordant sign with the slump test.5 The patient also presented with a localized left 8th rib injury involving the costochondral junction based on localized swelling and tenderness at the costochondral junction.7 There was no evidence of bony deformity or loss of disc height on plain radiographs (Figures 1 and 2). The patient demonstrated a noncapsular pattern of limitation at the thoracic spine. Thoracic rotation was more painful than side bending and left rib pain increased with cervical flexion during thoracic flexion testing. The patient’s rib pain was reproduced with neural tension (slump) testing and decreased with left ankle plantar flexion.5 Although rib springing test did not reproduce the patient’s pain, localized swelling along the 8th rib and tenderness at the costochondral junction indicated tissue inflammation.7

INTERVENTION

Physical therapy was recommended twice weekly with a treatment priority of spinal decompression6 to unload the thoracic IVD, as well as manual therapy and anti-inflammatory measures to reduce local rib pain and inflammation. Thoracic spine and rib pain decreased immediately during axial separation at the first visit (Figure 3). The patient was given instructions to perform 3-dimensional axial separation at home in right side lying (Figure 4) and thoracic IVD hydration management6 with a towel roll at T8 in a reclined position (Figure 5). Direct treatment to the left 8th rib costochondral junction included cross fiber massage (Figure 6) and iontophoresis with dexamethasone.

OUTCOMES

The patient was seen for a total of 4 PT visits. At his second visit, the swelling along the 8th rib had resolved and his thoracic pain had decreased to intermittent and 3/10 with thoracic rotation. At his fourth visit, he reported no pain in his thoracic spine and rib pain was minimal. The patient was transferring in and out of bed with no pain and he stated feeling ready to resume working out. He did not return to PT after his fourth visit due to his return to work. Five months following the patient’s last PT visit, he reported 0/10 thoracic and left rib pain, a Modified Oswestry Disability Index score of 0% disability and full return to work without restrictions. He was able to resume all pre-injury activities with no pain.

DISCUSSION

The patient described in this case report was initially suspected to have sustained a rib sprain following a work-related injury. However, the clinical examination revealed primarily an acute thoracic IVD lesion supported by pain provocation with thoracic rotation and positive dural tension signs. According to Sizer et al., once serious pathology has been ruled out, acute onset of pain in the thoracic spine region in the absence of trauma is most likely to be discogenic.5 Such IVD lesions can involve more severe characteristics such as herniation or more chronic features such as those seen in radial annular fissures, which are not typically evident with diagnostic imaging. The use of discography in the thoracic spine has shown correlation with the presence of annular fissures laterally provoking diffuse lateral trunk pain and posteriorly provoking local thoracic pain.8 Given that the thoracic nerve roots exit the dural sac higher in the segment than in the cervical or lumbar spine, radicular pain due to IVD pathology is rare because of the slim chance of exposure to IVD material.5 In contrast, as seen in this case presentation, dural irritation in the thoracic spine is very common. The unique anatomical variation of decreased volume of the thoracic spinal canal increases the likelihood that the cord and its dura will be affected, even with mild protrusions.5 In addition, the ligamentous attachments between the posterior longitudinal ligament, the dural sac, and the posterior anulus, increase the potential to provoke discogenic pain by means of neural tension tests. Tensioning the dural sac can pull on the outer aspect of the IVD, which is innervated by the sinuvertebral nerve and thus a pain generating structure. Approximately 75% of IVD lesions occur below T8 where the IVD is thicker and receives less support from the ribs.9

Biomechanical considerations supporting the diagnosis of acute thoracic IVD lesion in this case include evidence that the instantaneous axis of rotation for thoracic rotation is located in the posterior IVD.10 Consequently, segmental thoracic rotation, which is primarily controlled by the IVD, can provoke pain in the presence of IVD lesion.11 In addition, given the rotatory nature of this patient’s mechanism of injury, it stands to reason that the IVD sustained a pathological load leading to a painful condition.

The costochondral sprain was secondary to the complaints related to the thoracic IVD. Biomechanically, the ribs limit thoracic side bending range of motion.12 Consequently, primary rib injuries typically present with large, painful limits in thoracic side bending motion. Although this patient presented with evidence of tissue inflammation at the level of the rib, thoracic rotation and tensioning of the dural sac were more provocative of the patient’s pain.

CONCLUSION

Successful identification of the primary pain generating structure allowed for prioritizing management strategies. The patient responded well to IVD unloading and hydration management with full symptoms resolution. The acute nature of the case and the fact that the patient likely would have improved regardless of treatment is a limitation of this study. Addressing the costochondral injury with measures that decreased inflammation and promoted tissue healing helped to fully resolve the patient’s painful symptoms allowing him to return to his fitness and work activities with no restrictions. This case provides support for precise diagnosis and identification of pain generating structures in order to design plan of care. Larger trials are necessary to assess causation and if such treatment strategies are effective to manage patients with thoracic IVD conditions.

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