DATE OF OPERATION: MM/DD/YYYY
PREOPERATIVE DIAGNOSIS: L1 epidural mass.
POSTOPERATIVE DIAGNOSIS: Extruded disk at L1.
OPERATION PERFORMED:
1. L1 laminectomy and excision of extruded disk.
2. Intraoperative ultrasound.
3. Microdissection.
4. Use of intraoperative fluoroscopy, less than 1 hour.
SURGEON: John Doe, MD
ASSISTANT: Jane Doe, PA-C
ANESTHESIA: Local.
INDICATIONS FOR OPERATION: This is a (XX)-year-old female who did lifting and twisting while at work. She developed pain as well as weakness and numbness in the lower extremities. This was also associated with bowel and bladder dysfunction. An MRI demonstrated a large central epidural mass at L1 with severe conus medullaris compression, most consistent with an extruded disk fragment.
DESCRIPTION OF OPERATION: After informed consent was obtained, the patient was taken to the operating room. General anesthesia was administered. The patient was placed in the prone position on a Wilson frame, which was flexed. The lumbar area was prepped and draped sterilely. Local anesthetic was administered subcutaneously. Localizing needles were placed to identify the L1 level with intraoperative fluoroscopy.
A midline incision was made over the L1 level. The paraspinal muscles were stripped off the spinous process and lamina of L1. The spinous process of L1 was then removed using a rongeur. At this point, the operative microscope was brought into use, and the remainder of the procedure was performed using careful microdissection technique, including the use of microbipolar cautery, microscissors and microdissectors. This was done to prevent injury to the delicate neurovascular structures.
The lamina of L1 was thinned using the high-speed drill, and laminectomy was completed using Kerrison rongeurs. Dissection was continued laterally to expose the lateral thecal sac bilaterally. The exiting L1 nerve root was identified bilaterally. The thecal sac was then retracted medially, both above and below the L1 nerve, and the epidural mass could not be definitively palpated from either side.
Therefore, the level again was checked and again was confirmed to be the L1 level, and intraoperative x-ray was also obtained. Not being able to definitively palpate the lesion, an ultrasound was obtained, which did demonstrate the lesion at L1. On MRI imaging, this appeared to be an extradural mass, but because of its central location and difficulty of retraction of the thecal sac, it was not easily exposed. This was also the level where the conus medullaris was present, and therefore, excessive traction was not warranted. Because of this, it was felt that a transdural approach was necessary to gain exposure.
Therefore, a midline durotomy was made using a 15 blade, using microdissection techniques. The dura was opened in the midline. The arachnoid was sharply dissected. This afforded exposure of the conus medullaris and the exiting nerve roots of the cauda equina. With careful microdissection techniques, the posterior portion of the thecal sac was inspected. There was a protruding mass, which was extradural.
Therefore, the anterior dura was incised and disk material was encountered. This was sent for pathologic evaluation. Using microdissection techniques, large fragments of disk were able to be removed in this fashion. Exposure was performed on both sides, and no further disk material was removed.
The area was irrigated with excellent hemostasis. The conus medullaris and the exiting nerve roots were well protected. The dura was then closed with 4-0 silk suture. Tisseel was placed on the durotomy site. Gelfoam was placed in the lateral gutters and additional Tisseel was applied. The incision was closed with multiple layers of Vicryl suture. The skin was closed with a running nylon suture and dressed sterilely.
