Minimally Invasive Approach for the Treatment of Intradural Spinal Pathology

Ravi H. Gandhi, M.D; John W. Germ an, M.D.


Neurosurg Focus. 2013;35(2):e5 

In This Article


Of the 26 patients who underwent surgery for intradural spinal pathology via an MIS approach, 14 were female and 12 were male. Ten of 26 patients presented with a chief complaint of pain. The remaining 16 patients presented with neurological deficits including 6 patients with myelopathy, 3 with urinary incontinence, 1 with paraplegia, 3 with gait instability, 1 with hand weakness, and 2 with paresthesia (Table 1).

A total of 14 intradural tumors were treated, of which 12 were extramedullary and 2 were intramedullary. There were 4 cervical, 6 thoracic, and 4 lumbar tumors. There were 4 meningiomas, 4 nerve sheath tumors, 2 hemangioblastomas, 1 myxopapillary ependymoma, 1 metastatic carcinoma, 1 neuroendocrine tumor, and 1 pseudotumor. Eleven patients had a complete resection confirmed during the operation and on postoperative imaging. The patient with the neuroendocrine tumor underwent a complete resection at the level treated; however, he had multiple metastatic lesions with diffuse dural enhancement. Two patients underwent a biopsy for diagnosis as well as decompression. The remaining conditions treated included 4 Chiari decompressions, 4 arachnoid cysts, 3 tethered cords, 1 syringosubarachnoid shunt, and 1 midline myelotomy and cordotomy for chronic visceral pain from cancer.

The mean intraoperative blood loss was 197 ml (range 15–900 ml). Only 1 patient required a blood transfusion, and this was related to anemia from chronic disease due to her cancer rather than anemia from the surgery. One patient had a fusion at the time of surgery due to complete removal of the ipsilateral facet. Another patient required subsequent fusion at the level above the surgery. This patient was symptomatic from degenerative disc disease and had already had spinal surgery at other levels in the past, suggesting that the need for fusion was unrelated to the tumor resection surgery. There were no conversions to open traditional surgery and no postoperative CSF leaks. Seventy-five percent of Chiari decompression patients had pseudomeningoceles that were seen on postoperative imaging, but none were symptomatic. Two patients died within 90 days of surgery, but both deaths were related to the patients' primary disease and not to the surgery itself. One patient was readmitted with aseptic meningitis after Chiari decompression and another patient was readmitted for abdominal pain and nausea. Neither of those patients required any further surgical treatment. One patient required a return to the operating room 2 weeks after surgery for wound dehiscence; however, there was no infection or CSF leakage noted at that time. One patient required repeat surgery for further fenestration of a large arachnoid cyst. The cyst had multiple septations; therefore the second surgery addressed another compartment of the cyst at another level (Table 2).

All patients were mobilized and ambulatory within 24 hours of surgery except for 1 patient who underwent a midline myelotomy and cordotomy for intractable visceral pain and another with metastatic carcinoma. The mean length of stay in the hospital was 3 days; 22 patients were discharged home, 4 went to rehabilitation, and 1 died. At the time of the writing of this paper, 1 patient had increased neuropathic pain after surgery, 7 patients (26%) had complete resolution of their chief complaint, 10 patients (37%) improved with minimal residual problems, and 7 patients (26%) remained stable. One patient died of cancer-related complications. Another patient with intractable visceral pain from cancer requiring long-term intravenous medication drips was able to be weaned off the medication and discharged to home after a midline myelotomy and cordotomy.