Full Endoscopic Excision of a Large Intradural Extramedullary Tumor: A Technical Note

Kanthila Mahesha; H. Shatananda Prasad Rao

doi:10.21182/jmisst.2025.02425

Abstract

Traditional surgery for spinal tumors involves midline incision, extensive dissection, muscle damage, blood loss, ligament injury, and bone removal, with an elevated risk of complications. In contrast, minimally invasive techniques cause less soft tissue trauma, bleeding, infections, cerebrospinal fluid leaks, while enabling shorter hospital stays, and yielding similar results compared to open surgery. There have been reports of prior studies have reported the full endoscopic excision of small intradural extramedullary tumors. Here we report a case of a large intradural extramedullary tumor treated with a full endoscopic translaminar approach and dural repair.

Key Words: Full endoscopy, Intradural tumor, Dural repair, Schwannoma

INTRODUCTION

Traditional surgery for spinal tumors involves midline incision, extensive dissection, muscle damage, blood loss, ligament injury, and bone removal with increased risk of complications. Minimally invasive techniques for intradural extramedullary tumors cause less blood loss, cerebrospinal fluid (CSF) leaks, shorter hospital stays, and similar results compared to open surgery [1]. Endoscopic spinal surgery has gained increasing popularity over the past 10 years. Its muscle-preserving nature, reduction in postoperative pain, shorter hospitalization, and lower complication rates have contributed to the growing number of surgeons adopting this technique year after year [2].

Percutaneous full endoscopic excision of small intradural extramedullary tumors has been reported [3]. Here we report a case of a large intradural extramedullary tumor treated with a full endoscopic translaminar approach and dural repair. To our knowledge, this is the first time where a 3-cm-long tumor excision and dural repair by full endoscopic technique is reported.

MATERIALS AND METHODS

1. History and Examination

A 65-year-old female presented to us with severe low back pain radiating to both lower limbs. The patient had paresthesia and decreased sensations over the lateral aspect of both thighs. The patient was unable to walk even for a short distance. The patient was unable to perform her day-to-day activities due to severe pain. The pain was disturbing the sleep. The patient did not have bowel or bladder involvement. The patient did not have medical comorbidities. Neurologic examination revealed intact motor power, sensory blunting over both L5 dermatomes, and absence of knee and ankle jerks bilaterally. The patient had intact posterior column sensations.

A written informed consent for publication was obtained from the patient.

2. Imaging Studies

A magnetic resonance imaging of the lumbar spine (with contrast) showed a well-defined intradural oblong altered signal intensity (T1-iso to hypotense, T2/STIR [short tau inversion recovery]-hypertense) lesion showing heterogeneous postcontrast enhancement with ill-defined nonenhancing areas within the spinal canal (enhancing areas show hyperintense signal on T2) at the level of the L2–3 vertebrae measuring 9.7 mm × 12 mm × 35 mm (anteroposterior × transverse × craniocaudal). The lesion is seen abutting and displacing the traversing nerve roots laterally and posteriorly at the L2–3 level and the cauda equina nerve roots and filum terminale posteriorly. Anteriorly, it is seen abutting the posterior aspect of the L2–3 disc. CSF space is not visualised at this level (Figure 1).

3. Surgery

A full endoscopic translaminar approach was planned to remove this large tumor through a 1-cm skin incision. General anesthesia was used for this case. Neuromonitoring was not used in this case.

4. Surgical Steps

1) Exposure of dura

The patient was positioned prone on the operation theater table, and using fluoroscopic guidance, the L2–3 level was marked using a 21G needle. Using aseptic precautions, parts were scrubbed, painted and draped. A 1-cm-long transverse skin incision was made at the L2–3 level just lateral to the midline. An 8-mm dilator was passed to land on the L2 lamina. A 9.4-mm cannula was passed over the dilator, and a 5.7 mm × 8.4 mm × 125 mm 15° endoscope was introduced. Superficial muscle dissection was done using monopolar electrosurgery to expose the L2 lamina, pars and ligamentum flavum. Using an endoscopic drill, laminotomy of L2 was done. The pars interarticularis and facet joints were preserved. The base of the spinous process was drilled to have enough space for dural repair. The ligamentum flavum was released with a curette and removed using endoscopic Kerrison rongeurs to expose the dura.

2) Exposure and excision of tumor

The dura was opened using an endoscopic dural knife (Figure 2A). The dural opening was 10 mm. The arachnoid membrane was released with a dissector to expose the roots. The caudal edge of the tumor was exposed using a 4-mm tubular root retractor (Figure 2B). The caudal end of the tumor was grasped with a 2.5-mm grasper (Figure 2C) and slowly delivered out of the dural opening along with the root retractor. Blood vessels over the tumor were coagulated using a radiofrequency probe (Figure 2D). The tumor was held with a 4-mm grasper (Figure 2E) and delivered out en bloc. Endoscopic inspection did not reveal any residual tumor inside the dural sac. Roots had come out through the dural opening (Figure 2F). The tumor measured 3 cm × 1.2 cm × 1 cm (Figure 3) and correlated with the preoperative magnetic resonance imaging (MRI) images. Tissue was sent for histopathology.

3) Dural repair

Roots were pushed inside the dural sac using a cotton pattie (Figure 4A). Dural repair was done by a full endoscopic monoportal technique using 6-0 Prolene sutures. The endoscopic needle holder designed by the author was used to hold the 6-0 Prolene. A bite was taken over the 2 dural edges (Figure 4B), and the needle was pulled out. The 2 ends of the thread were held outside, and a simple knot was made. The knot was pushed inside through the endoscope using an endoscopic knot pusher (Figure 4C). Another simple knot was taken outside, and the knot was tightened using a knot pusher. We used 4 to 5 knots to avoid loosening and failure. Excess sutures were cut using an endoscopic annular cutter (Figure 4D). The cotton pattie was removed, and the second dural suture was taken (Figure 4E). Simple knots were taken and tightened using a knot pusher as described earlier. There was no root herniation at the end of the repair (Figure 4F). The Valsalva test was done to confirm the adequacy of repair. We did not use any glue or patches over the repair site. Two simple interrupted sutures are enough for the repair of a 1-cm dural incision. The endoscope and cannula were removed. Skin was approximated with a single subcutaneous Vicryl 3-0 suture. No drain or skin sutures were used. The procedure was completed in 4 hours.

RESULTS

The patient was observed in the postoperative ward for 6 hours. The patient was mobilized 4 hours after the surgery. The patient was completely relieved of radiating pain and sensory deficits. The patient was discharged on the second postoperative day. The patient had minimal operative site pain that was managed with oral analgesics for 1 week. We did not use steroids postoperatively. There was no intraoperative or postoperative complication. There was no postoperative neurologic deterioration. The patient resumed her work as a homemaker one month after the surgery. An MRI scan done 2 months after the surgery revealed complete removal of the tumor, excellent decompression, and normal orientation of roots and CSF space (Figure 5). The histopathology report was suggestive of a benign schwannoma. At the 6-month follow-up, the patient was clinically asymptomatic.

DISCUSSION

Traditional laminectomy for excision of spinal tumors involves a large midline skin incision, extensive muscle and ligamentous dissection, and bilateral laminectomy along with removal of the spinous process to reach the tumor. It also includes dissection and removal of the interspinous and supraspinous ligaments, which form an important component of the midline posterior tension band crucial for stability, and damage to this can lead to delayed degeneration, instability, and postlaminectomy kyphotic deformity [4]. Most often these open procedures need posterior instrumentation for postexposure instability. Literature reviews conclude that minimally invasive techniques cause less soft tissue trauma, bleeding, infections, CSF fistula, shorter hospital stays, and similar results compared to open surgery [1,4].

In 1998, Frank [5] reported on the endoscopic suction decompression of an epidural lipomatosis at L5–S1. Telfeian et al. [6] in 2015 reported a ventral epidural tumor at the T6 level treated with a transforaminal endoscopic procedure. Ying et al. [7] performed epidural angiolipoma excision at the L2–3 level via a percutaneous endoscopic intralaminar approach. Şentürk [8] in 2019 removed an intradural tumor through endoscopic technique. However, the dura was not sutured, and tissue glue was applied on top of the dura. Hagel and Isseldyk [3] reported full endoscopic excision and dural repair of a small intradural extramedullary tumor at the L1 level.

Full endoscopic exposure of the dura is not difficult. However, it is very important to avoid iatrogenic neural injury during exposure. We avoided inserting any instrument into the canal during exposure. Bone removal was done using burrs. The ligamentum flavum was released using a curette and removed using graspers. The dura was opened using an endoscopic dural knife. Endoscopic exposure of the tumor is challenging because of the single port. In this case, we used a tubular root retractor with a 5-mm outer diameter and a 4-mm inner diameter. With this root retractor, we were able to displace the roots and expose the caudal end of the tumor. Once the caudal end of the tumor was exposed, it was held with a 2.5-mm grasper and gently pulled out and away from the neural structures. The tumor was delivered out of the dura en masse, and coagulation of the feeder vessels was done. In this case, there were no rootlets attached to the tumor. When rootlets are attached to the tumor, they may be released or resected. Then, the tumor was held with a 4-mm grasper and delivered out of the wound along with the scope. Once the tumor was removed, roots herniated out of the dura. Lowering the head end can help in getting the roots inside the dura, but there is a risk of pressure-related complications in full endoscopic surgery. We had used a 1-cm × 1-cm cotton pattie to push the roots inside the dura. We had kept 5 mm of thread attached to the cotton pattie for easy identification and removal. This technique helped in dural repair by keeping the roots safe inside the dural sac. The cotton pattie was removed after securing the first dural suture. There was no root herniation afterwards. This is a novel technique for full endoscopic surgery. By using a cotton pattie, we are able to manage the dural openings and the roots. The addition of a second dural suture was sufficient for the 1-cm durotomy repair.

Dural opening may increase the risk of complications specific to full endoscopic spine surgery, such as severe headaches, seizures, and visual disturbances [9]. We do not use a pressure pump for saline irrigation. We used saline bags under gravity, which provided uniform pressure without the fear of pressure-related complications.

Dural tears undetected or not properly closed can cause postural headache, nausea, vomiting, pain or tightness in the neck or back, dizziness, diplopia due to VI cranial nerve paresis, photophobia, tinnitus, etc. Furthermore, CSF leakage following dural tears can pose potentially serious complications such as CSF fistula formation, pseudomeningocele, meningitis, arachnoiditis, epidural abscess, and, rarely, death [10]. That is why it is preferred and advised to repair the dura to avoid the above-reported complications.

However, primary closure of a dural tear via suturing remains challenging because of the limited working space in endoscopic surgery [11]. Lack of specific instruments makes endoscopic dural repair difficult. Shin et al. [12] reported full endoscopic dural repair with basic endoscopic instruments such as a ring curette and a 6–0 prolene suture. Trathitephun et al. [13] reported endoscopic dural repair with basic endoscopic instruments such as forceps, laparoscopic knot pushers and a 6–0 prolene suture. We have used a custom-made endoscopic needle holder and knot pusher for dural repair. Needle holder and knot pushers make full endoscopic dural repair easier. We have used 6-0 prolene 3/8 circle taper point double-armed sutures. In this case, we used the out-in-out technique of dural repair. Another option is to use the inside-out technique on both sides using 2 needles and then tie the knot. In this case, the dural opening was 1 cm, and 2 interrupted sutures were sufficient for dural closure. We were confident of the repair and did not use any dural patch or glue. To the best of our knowledge, this is the first case report where a 3-cm-long intradural extramedullary tumor was removed en bloc with dural repair by full endoscopic technique. We used a dedicated set of instruments designed by the first author, for this surgery (Figure 6).

Complete excision of a well-loculated large intradural extramedullary tumor is possible with a full endoscopic technique. Full endoscopic excision of intradural extramedullary tumor and dural repair is the least invasive technique. Advantages of full endoscopic tumor excision include a short hospital stay, minimum blood loss, early recovery, and reduced complications. Despite these advantages, the endoscopic tumor excision and dural repair are difficult to perform and should be done only by an experienced endoscopic surgeon with the necessary instruments and techniques.

CONCLUSION

Full endoscopic intradural tumor removal and dural repair is the technology for the future. This technique has a faster recovery time, less blood loss, an earlier return to day-to-day activities, and fewer complications compared to traditional procedures. However, full endoscopic intradural tumor excision and dural repair should be performed only by an experienced endoscopic surgeon with proper instruments.