orthopedic paper IV
Lipoma under soft spinal membrane complicated with high paraplegia
Introduction
Intraspinal tumors predominantly consist of extramedullary tumors, accounting for 85% of the cases. However, subdural lipomas are exceedingly rare. Due to their proximity to the spinal cord, the pathological changes and clinical symptoms often get confused with intramedullary tumors. Nevertheless, as benign lesions, their surgical treatment and prognosis differ significantly. We report a case admitted to our hospital who has fully recovered after six months post-surgery.
Case Presentation
The patient is a 39-year-old married male farmer from our county, admitted on March 28, 1979, with case number 1340. He experienced numbness and weakness in both lower limbs accompanied by sharp, band-like pain on the right side of the chest for six months. He had difficulty with bowel and bladder control and was unable to walk or stand for two months. Paralysis had ascended to the level of the nipples, accompanied by breathing difficulties for two weeks.
Clinical Examination
Superficial sensation below the second rib was virtually absent, more so on the right side. Partial sharp pain remained on the left side. Abdominal and cremasteric reflexes were absent. The muscle strength in both lower limbs was graded 8-4, and there were no ankle clonus. Tenderness was observed upon percussion of the spinous processes of the upper thoracic vertebrae, but no deformity was noted. Thoracic spine X-rays were negative. Queckenstedt's test showed complete obstruction of the subarachnoid space. CSF analysis: Pandy's test positive, cell count 10/mm³, and positive for Froin's sign. Paralysis index was 2-4 (sensory 2, motor 1, sphincter 1).
Preoperative Diagnosis
Cervicothoracic intraspinal tumor with paralysis, extramedullary type.
Surgery
On April 4, intraspinal exploration was performed under local anesthesia. Via a posterior midline approach, the laminae of thoracic vertebrae 7-12 were excised. The dura was opened between cervical 6 and thoracic 5. Although fat distribution seemed uniform in the epidural space, a 35x20x12 cm fatty, yellow, soft protrusion was discovered on the dorsolateral aspect of the spinal cord at T1:T2, causing 50% compression. The lesion was partially excised (80%) to avoid spinal cord injury, tagged, and sent for pathology. The surgical field was irrigated. The dura was left open to decompress, and the soft tissues were sutured without drainage.
Postoperative Recovery
Within 48 hours post-surgery, the patient reported a burning sensation in both lower limbs. Gradually, motor and sensory functions improved. On postoperative day 19, the urinary catheter was removed, and the patient could urinate voluntarily and turn himself over. He was discharged after 36 days without any complications.
Pathological Report
The protrusion was identified as "fatty tissue," pathology number 4724.
Six-Month Follow-Up
Six months postoperatively, the patient can walk with crutches, has completely regained sensation, has normal bowel movements, and has normal urinary flow. His appetite is good, nutrition is well-maintained, and he can engage in weaving and other handcrafts.
Discussion
Intraspinal tumors that reside underneath the soft dura mater are, for the most part, growths that overlay the spinal cord. These growths create a space-occupying pressure that leads to spinal canal obstruction, a mechanism distinct from intramedullary tumors that directly damage the spinal cord. While the former mostly consists of benign abnormalities, the latter are primarily malignant. However, both can cause early-onset paraplegia due to their close relationship with the spinal cord, and both can advance rapidly. In this case, the "lipoma" is a benign growth that, within a short span of six months, caused severe obstruction of the spinal canal.
In the case of intramedullary malignant tumors, such as gliomas, paraplegia appears early and is often complete. Benign growths close to the spinal cord usually cause more severe paralysis on the side where the growth is present, commonly known as Brown-Séquard syndrome. This case exhibited varying degrees of paralysis on both sides, with early-onset "intercostal neuralgia" on the right side, which correlates with the intraoperative finding of the growth leaning to the right. Additionally, bladder and rectal functions were not completely impaired.
Clinically, progressive paraplegia accompanied by evidence of obstruction in Queckenstedt's test indicates the need for early surgical intervention to relieve the pressure. Even if the abnormality is benign, prolonged pressure can cause irreversible damage to the spinal cord. Relaxing paralysis, even if it lasts for several weeks, is hard to reverse. In our case, timely surgical decompression yielded good results.
Based on clinical symptoms, the level of paralysis, and tests like Queckenstedt's and spinal angiography, it is possible to understand and locate the spinal canal obstruction. Intraoperatively, the effectiveness of decompression can be judged by the return of pulsations in the spinal cord. When the growth cannot be completely removed, it's crucial to leave the dura mater open as a decompressive measure.
Soft dura mater lipomas are soft, benign tissues. They don't cause localized fatty absorption on the hard dura and show no localized elevation or hardening, making them hard to detect from outside the dura mater. When the dura is cut open, these growths can be clearly identified: a yellow growth overlaying the spinal cord with increased, abnormal vascular distribution, flattening the spinal cord due to pressure.
Conclusion
This paper reports a rare case of a lipoma underneath the soft dura mater, leading to high-level paraplegia. It analyzes the case from a pathological and clinical perspective, comparing it with intramedullary tumors. It suggests that surgical intervention should be performed as early as possible. However, it's not necessary to "completely" remove the tumor; spinal decompression is crucial.
This article was presented at the Second Sessiong of Third Annual Surgical Conference in Anhui Province and originally published in "Nanling Medicine" 1979；1:68. Nanling Hospital, Li Mingjie
from 软脊膜下脂肪瘤并发高位截瘫
