POSTOPERATIVE DIAGNOSIS: Right inguinal chronic neuropathic pain.
PROCEDURE: Right groin exploration with double neurectomy (ilioinguinal and iliohypogastric).
ANESTHESIA: General endotracheal anesthesia.
SPECIMENS:
1. Ilioinguinal nerve candidate, frozen.
2. Iliohypogastric nerve candidate, frozen.
3. Ilioinguinal nerve candidate #2, frozen.
4. Iliohypogastric nerve candidate #2, frozen.
5. Additional iliohypogastric nerve tissue, permanent.
6. Additional ilioinguinal nerve tissue, permanent.

INDICATION FOR PROCEDURE: This is a female who underwent an open right inguinal hernia repair approximately a year and a half ago who since that time has had severe disabling neuropathic pain that has been refractory to medical management with pain medication, steroid injections, and nerve blocks as well as management with amitriptyline and Lyrica. Patient seen in clinic approximately 4-5 months ago and performed dermatome mapping on 2 different occasions. Her overall pain distribution appeared to be most severe in the ilioinguinal nerve distribution. Review of the previous surgeon’s operative report noted difficulty in identifying the ilioinguinal nerve at the time of the index operation. Additionally, the mesh was secured with Prolene sutures. CT scan showed no evidence of hernia recurrence or anatomic abnormality to explain her pain. It was felt that she most likely had an ilioinguinal nerve entrapment or injury.

DESCRIPTION OF PROCEDURE: The patient was taken to the operating room and placed in supine position with her arms extended bilaterally. General endotracheal anesthesia induced. Once the patient was asleep, her abdomen was prepped and draped in customary sterile fashion. SCD boots were placed on lower extremities and activated. She received Ancef for surgical site infection prophylaxis. Hard stop timeout procedure was observed.

We created a skin incision with a 15-blade scalpel incorporating the previous incision and extending it approximately 2 cm lateral. We dissected through subcutaneous tissue, which had a moderate amount of scarring and obliteration of the normal anatomic planes. By dissecting laterally outside of the previous dissection plane, we were able to identify the fibers of the external oblique as well as to identify Scarpa fascia mixed in with scar tissue in the subcutaneous tissue. Dissection was then carried medially through the scar tissue along these planes and we were able to with careful combination of electrocautery and sharp dissection with 15-blade scalpel identify planes and separate the subcutaneous tissue and Scarpa fascia off of the underlying fibers of the external oblique.

We were able to identify at least 2 Prolene sutures which appeared to be visible through the external oblique. Initially, this position was somewhat confusing, but after we were able to open the external oblique laterally and dissect it medial, it became clear that these were the knots of the Prolene used to secure the previous mesh into the transversalis fascia and that they had actually eroded through some of the fibers of the external oblique aponeurosis. Once we were able to open the external oblique, we were able to dissect it free on the underside and identify the lateral edge of the previously placed mesh which appeared well incorporated without any signs of infection or abnormality. There was no evidence of recurrent hernia by inspection or palpation.

By dissecting lateral to the lateral edge of the mesh, we were able to identify 2 candidate structures less than 1 cm apart and approximately 1 cm superior to the level of the inguinal ligament, which appeared consistent with nerve tissue. This had a somewhat more attenuated appearance than is typical for the ilioinguinal nerve, which is consistent with the previous surgeon’s operative description of having difficulty finding it. It did almost appear to be partially intramuscular at this point. This did appear to course lateral to medial, but was unclear in anatomy once it reached the lateral aspect of the mesh as the entire field had incorporated and was a continuous scar tissue around the mesh.

There was no evidence of hernia recurrence, and the patient’s symptoms were relatively mild in the genital branch of genitofemoral distribution. I did not feel that dissecting the mesh off the floor of the inguinal canal would be of benefit soley to identify this nerve as the pain distribution did not favor this nerve branch having signficant involvement. I was also concerned this dissection would cause a new hernia to form complicating her overall care.

Once we identified these 2 candidate appearing structures, it was unclear whether this represented the ilioinguinal and iliohypogastric as they were closer together than normal distribution given the patient’s relatively small frame or whether this could be an aberrant anatomical division of the ilioinguinal. Both sections were encircled and ligated proximally at the level of the muscle fibers with 3-0 Vicryl and tucked into muscle fibers as much as able. Approximately 1-cm section of each was divided and dissected medial until entering the obliterated scare tissues at the lateral edge of the mesh; they were passed off for frozen specimen. The first candidate nerve tissue was confirmed to have neuro bundles consistent with nerve tissue by frozen section. The second candidate nerve resection again was also confirmed to have nerve tissue under frozen section.

Due to the relatively low positioning of both of these and concern that the iliohypogastric may be still present, we did explore superior by dissecting the external oblique aponeurosis off the underlying internal oblique aponeurosis until the transition from the muscular to the aponeurotic part was clearly visible. In this area, approximately 2 cm to 3 cm above the previously ligated nerve tissue, there were several areas of nerve-like appearance in one case which was somewhat intermuscular which would be expected for the anatomic position of the iliohypogastric at this level. Two of these nerve appearing bundles were dissected free, ligated proximally with 3-0 Vicryl, and submitted for frozen section similar to the previous nerve-like structures.

On frozen section, the pathologist did not feel confident determining whether this was nerve tissue or not. He did note the presence of spindle cells, but did not have the clear organized structure that was visible in the previous 2 specimens. He felt permanant staining for S-100 would be more definitive. We further examined the area, as well asthe lower area where we had previously sent the initial 2 frozen sections, and noted some additional small and thin additional tissue that appeared modestly consistent with nerve structures. Out of an abundance of precaution, we submitted these additionally as well.

At this point, we did make an attempt to identify the round ligament and the internal ring of the mesh, but the entire area was significantly scarred in and the dissection planes were somewhat difficult to develop. A small 3-mm hole was created in the inferior leaflet of the external oblique aponeurosis during this dissection. Due to the distribution of the patient’s pain, I did not feel an extended search for the round ligament or the genital branch would be of any significant benefit to the patient and we elected to not perform an extended neurectomy due to her relatively small frame and concern that this could lead to injury of the iliac vein.

Once we had completed careful examination and dissection for any additional nerve-like structures in this region, we felt there was no additional benefit to continue the exploration. We did identify 3 Prolene sutures that appeared to be sutures suturing the mesh to the transversalis fascia, and these were excised. Once this dissection and removal was complete, we closed the external oblique aponeurosis with a running 3-0 Vicryl suture and we closed the Scarpa fascia with a running 3-0 Vicryl suture and then closed the skin with running 4-0 Monocryl subcuticular stitch and applied Dermabond.[/SIZE]