Four patients underwent lumbar surgery. In all four patients, the dura was minimally torn during the operation. However, none exhibited signs of postoperative cerebrospinal fluid leakage. In each case, a few days after the operation, the patient suddenly experienced severe recurring pain in the leg. Repeat magnetic resonance imaging showed transdural nerve rootlets entrapped in the intervertebral disc space. On exploration, ventral dural tears and transdural nerve rootlet entrapment were confirmed. Midline durotomy, herniated rootlet repositioning, and ventral dural tear repair were performed, and patients' symptoms improved after rootlet repositioning. Even with minimal dural tearing, nerve rootlets may become entrapped, resulting in severe recurring symptoms. Therefore, the dural tear must be identified and repaired during the first operation.
Transdural nerve root entrapment in the intervertebral disc space after incidental durotomy during lumbar disc surgery very rarely causes severe recurring radiating pain. The treatment of dural tear has evolved through time. Bed rest alone is no longer the definitive treatment for dural tear
A 52-year-old female presented with a 2-month history of low back pain and right leg pain. Preoperative magnetic resonance imaging (MRI) showed disc herniation at L4-5 on the right side (
A 66-year-old male presented with a 1-month history of back pain and left leg pain. Initial MRI showed disc bulging at L2-3 and L3-4 and foraminal stenosis at L4-5 bilaterally (
A 49-year-old female had back pain and left leg pain for 6 months. Initial MRI showed extraforaminal disc herniation at L4-5 on the left side (
A 59-year-old female presented with a 1-month history of back pain and bilateral leg pain, more severe on the left. Preoperative MRI showed disc herniation at L1-2, ossification of the posterior longitudinal ligament (OPLL), central spinal stenosis at L1-2, and fusion of L2-3-4-5 with pedicle screws (
The recurrence of radiating pain after spinal surgery has many causes. Recurrent disc herniation, remnant herniated disc material, postoperative epidural hematoma, and nerve root inflammation can all cause recurrence of this radiating pain. A few studies have reported rare causes of postoperative recurrence of radiating pain, such as the presence of a pseudomeningocele and posttraumatic spinal cord or nerve root herniation through a dural defect site
The incidence of unintended intraoperative durotomy is between 0.3% and 17.4% and varies depending on the type of surgical procedure
The mechanism postulated for nerve root entrapment in the intervertebral space is a water-hammer effect resulting from the difference between the intradural pressure and the intervertebral space pressure
Rootlet entrapment can be diagnosed by MRI. The typical appearance of rootlet entrapment is a beak-like appearance of the ventral dura and rootlet in the sagittal view. In the axial view, the entrapped rootlets are located in the intervertebral disc space. A magnetic resonance myelogram can also show CSF leakage into the involved disc space. However, the diagnostic value of myelography is limited if the subarachnoid space does not extend outside the dural space. Before exploration, it is important to obtain a radiographic image to confirm the location of the dural defect.
An iatrogenic dural tear causes a poor clinical outcome
Surgically accessing the ventral or lateral side of the dura is difficult
In our four cases, prompt diagnosis and operation were performed in all cases except case number 2. In case 2, correct diagnosis was delayed and the patient suffered from radiating pain for several months. However, postoperatively, there was no neurologic deficit, and there was good improvement in all cases. If a patient presented with recurrent pain after brief improvement, the surgeon must cautiously watch the operated level first.
Iatrogenic thinning and tearing of the dura can cause rootlet entrapment even if the dura is minimally torn. The results obtained for our cases indicate that complete surgical repair of the ventral dura defect is required to prevent nerve rootlet entrapment and other complications, even if the dural defect is minimal. If a dural tear is suspected, a Valsalva maneuver should be performed before wound closure even if there is no CSF leakage.
Before the operation : disc herniation at L4-5 on the right side (white arrow). A-1. Sagittal magnetic resonance image. B-1. Axial magnetic resonance image. After the operation : good decompression of L4-5. A-2. Sagittal magnetic resonance image. B-2. Axial magnetic resonance image. Rootlet herniation : rootlet herniating into the intervertebral disc space at L4-5 on the right side (black arrow). A-3. Sagittal magnetic resonance image. B-3. Axial magnetic resonance image.
Before the operation : disc herniation at L2-3, L3-4, and L4-5. A-1. Sagittal magnetic resonance image. B-1. Axial magnetic resonance image showing disc herniation at L2-3 on the left side. Rootlet herniation : rootlet herniating into the intervertebral disc space at L2-3 on the left side (white arrow). A-2. Sagittal magnetic resonance image. B-2. Axial magnetic resonance image of L2-3. Myelogram : magnetic resonance myelogram showing intradiscal leakage of cerebrospinal fluid (white arrow).
Initial magnetic resonance image : extraforaminal disc herniation at L4-5 on the left side. A-1. Sagittal magnetic resonance image. B-1. Axial magnetic resonance image of L4-5. Before the operation : paramedian disc herniation and extraforaminal disc herniation at L4-5 on the left side. A-2. Sagittal magnetic resonance image. B-2. Axial magnetic resonance image of L4-5. Rootlet herniation : rootlet herniating into the intervertebral disc space at L4-5 on the left side (white arrow). A-3. Sagittal magnetic resonance image. B-3. Axial magnetic resonance image of L4-5.
Before the operation : disc herniation with osteophyte at L1-2 (white arrow). A-1. Sagittal magnetic resonance image. B-1. Axial magnetic resonance image of L1-2. Rootlet herniation : rootlet herniating into the intervertebral disc space at L1-2 (white arrow). After the operation : herniated rootlets were reposited.