Case Studies

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38 year old laborer who had the immediate onset of left leg burning pain and weakness after lifting a heavy load. He had onset of some bladder incontinence (which is a surgical emergency).

Images A and B show the very large L4-5 lumbar disc herniation with marked impingement on the neural canal. 

The patient underwent emergent microdiscectomy. He had improvement of his bladder incontinence and improvement of his leg burning pain and weakness. He did have some residual weakness and persistent pain due to the large size of the disc herniation and probable permanent nerve impingement. 

Images C and D show a post-operative MRI scan which reveals removal of the large disc herniation. Note how the disc signal continues to be abnormal, since the disc cannot be returned back to ‘normal’. Although most patients have marked improvement of their leg pain, this patient did develop persistent back and leg pain that required further treatment.

History

The patient, aged 54-years, is an avid skier and mountain biker who presents with a sudden right foot drop after skiing. She had a transient left leg radiculopathy that improved with a bilateral L4-L5, L5-S1 transforaminal epidural steroid injection. However, persistent weakness in right ankle dorsiflexion has prevented her from returning to her activities.

Her history includes degenerative scoliosis, which has been well-managed with nonoperative care. Previously (2012), she underwent right L4-L5 microdisectomy. Examination

Examination

The patient is pleasant, appropriate to the situation, interactive and a reliable historian.

musculoskeletal examination, lower extremities
  • Sensation to light touch is decreased, right lateral calf
  • Reflexes (R/L): 1+/1+ knees and 0/1+ankles
  • Straight leg raise (SLR): Negative bilaterally
  • Hip range of motion: No reproduction of pain
  • No atrophy of the quadriceps or gastrocsoleus
  • No edema
  • Pulses (R/L): 2+/2+ posterior tibial

Pretreatment Imaging

Anteroposterior (Figure 1A) and lateral (Figure 1B) x-rays of the lumbar spine.

Anteroposterior and lateral x-rays of the lumbar spine

Flexion (Figure 2A) and extension (Figure 2B) x-rays of the lumbar spine.

Flexion and extension of the lumbar spine

Sagittal MRI (Figure 3A) denotes L4; Figure 3B is an axial view of L4-L5.

Sagittal view of L4 and axial view of L4-L5

Sagittal MRI denotes the L5 level (Figure 4A) and corresponding axial view of L5 (Figure 4B).

Sagittal MRI of L5 level and axial view of L5

Diagnosis

Recurrent L4-L5 herniated nucleus pulposus with right foot drop.

Selected Treatment

Right L4-L5 transforaminal endoscopic discectomy was performed.

Surgeon's Treatment Rationale

The patient is regularly active and maintains a high level of function. Surgical decision-making was focused on treating the acute problem of motor weakness due to the disc herniation while simultaneously allowing for a rapid recovery and return to activities. Her underlying scoliosis is a long-standing problem that has been managed nonoperatively, and the goal was to continue nonoperative treatment of this more extensive problem.

Procedure Description

The initial dilator is placed along the posterior annulus, within the canal (Figures 5A and 5B).

Intracanal technique, placement for intial dilator into the epidural space

Serial dilation is performed along with reaming to open the neuroforamen. The working cannula is then positioned to visualize the epidural space and annulus.

Disc fragments (stained with Indigo Carmine; see Figure 7B below) are identified and removed with pituitary ronguers. Straight and angled graspers are then used to pull out herniated disc fragments. Frayed edges of the annular tear are ablated using the Ellman radiofrequency probe and YAG holmium side-firing laser (Figures 6A, 6B, video) to complete the discectomy.

Disc fragments are identified and removed using straight and angled graspers
Surgical Video

The decompression is assessed by visualizing the traversing and exiting nerve roots, and probing the canal with the curved ball-tip probe (Figure 7A). The probe is observed to pass easily through the path of the exiting nerve root, across the midline of the canal, and down the path of the traversing nerve root, past the pedicle.

Ball-tip probe used to assess exiting nerve roots

Dr. Kim's laser endoscopic spine surgery website explains the procedure in more detail.

Outcome

The patient reported she has, "practically no foot drop while walking."

preoperature versus postoperative sagittal MRI musculoskeletal examination, lower extremities, preoperative versus postoperative
  • ODI: 10
  • VAS Back: 0
  • VAS Right Leg: 2-3
  • VAS Left Leg: 0

Case Discussion

Dr. Kim details the case of a patient with an L5 radiculopathy who presents primarily with weakness as opposed to pain. She failed a course of nonoperative therapy. Previously, she had a L4-L5 microdiscectomy.

Her imaging studies demonstrate a tremendous loss in lumbar lordosis, as well as a coronal plane deformity. There is no instability on the dynamic films. The patient was successfully treated with an endoscopic discectomy on the right at L4-L5. She made an excellent recovery in terms of motor function, but the date of follow-up is not provided.

This is an excellent case to consider. Although her imaging studies clearly show her spinal alignment is suboptimal, she does not have back pain and only presents with a radiculopathy. Therefore, Dr. Kim's choice to treat only the radiculopathy is most appropriate. It would be completely unreasonable to perform a major realignment and reconstruction at this point in time. Unfortunately, for this woman, at some point in her life, she will probably require more extensive surgery. However, as time passes, the techniques will improve and as that occurs, one would expect the risk of complication to decrease. Therefore, to allow her to be fully active at this time without a large fusion is the best choice.

Many surgeons do not use the endoscope and prefer to do these procedures using a minimally invasive approach with the microscope. This allows for true 3-D visualization and decreases the need for extra equipment in the operating room. Using either of these techniques has been reported to result in excellent outcomes. The key point of the specific surgical technique is that it helps preserve the supporting structures due to its minimally invasive nature.