Minimally Invasive Insertion of Syringosubarachnoid Shunt for Posttraumatic Syringomyelia: Technical Case Report

Subacute posttraumatic ascending myelopathy (SPAM): A potential complication of subarachnoid shunt for syringomyelia?

Context: Treatment of primary spinal syringomyelia is still controversial. Among others, shunting syrinx fluid to the subarachnoid, peritoneal or pleural space has been utilized with varying success. Shunt obstruction, migration, and infection represent the most common complications of these procedures. Findings: The authors present the case of an 81-year-old woman who developed an unusual neurological deterioration resembling a subacute posttraumatic ascending myelopathy (SPAM) after the insertion of a syringosubarachnoid shunt for the treatment of slow-growing D10 syringomyelia. Conclusion/Clinical Relevance: To date, no cases of SPAM secondary to the insertion of a syringosubarachnoid shunt for the treatment of syringomyelia have been reported. The potential pathogenesis related to this phenomenon is discussed.

Syringo-Subarachnoid Shunt Placement: A Minimally Invasive Technique Using Fixed Tubular Retractors-Three Case Reports and Literature Review

BACKGROUND

Placement of a syringo-subarachnoid shunt as a surgical management for syringomyelia has been well described in the literature. Good results in terms of clinical and radiological improvement have been documented especially for posttraumatic syringomyelia. Traditionally, this has been performed using open approaches which are fraught with risks of cerebrospinal fluid leak, delayed wound healing, and increased postoperative pain. With the help of minimally invasive techniques that are currently being used to treat various degenerative spinal disorders, most of these complications may be minimized. However, few reports in literature describe similar approaches for accessing intradural intramedullary spinal cord lesions and especially for syringomyelia.

METHODS

Retrospective case review: using a 22-mm tubular retractor, a laminotomy was performed, durotomy done, and spinal cord identified. Myelotomy was performed at the dorsal root entry zone, syrinx visualized and entered, followed by placement of syringo-subarachnoid shunt.

RESULTS

Three male patients aged 44, 57, and 37 underwent placement of syringo-subarachnoid shunts using minimally invasive fixed tubular retractors. Indications included posttraumatic or postsurgical spinal cord syrinx. Follow-up period was 1 year in all cases. There were no neurological or technique-related complications. All patients showed clinical improvement upon subsequent follow up.

CONCLUSIONS

Our clinical experience on the treatment of syringomyelia via a minimally invasive fixed tubular retractor is presented. We find that this is an ideal approach for placement of syringo-subarachnoid shunts, as it provides direct access to the lesion with minimal collateral damage and wound-related complications.

LEVEL OF EVIDENCE

4.

CLINICAL RELEVANCE

Relevant - in demonstrating the effectiveness of an already established procedure through a novel, minimally invasive approach which has the potential to significantly reduce the overall morbidity, in view of the inherent approach-related benefits as compared to conventional open approaches.

Post-traumatic syringomyelia: CSF hydrodynamic changes following spinal cord injury are the driving force in the development of PTSM

Post-traumatic syringomyelia (PTSM) is a disorder that occurs infrequently following spinal cord injury (SCI), characterized by progressive neurological deterioration resulting from syrinx expansion originating in proximity to the traumatic epicenter. Several pathogenetic factors are associated with this disorder, however, the precise mechanism of the development of PTSM is controversial. Combined anatomical alterations and molecular changes following trauma to the spinal cord and arachnoid participate in the development of this condition. These factors include narrowing or obstruction of the subarachnoid space (SAS), central canal occlusion, myelomalacia, and alterations in intramedullary water permeability. If a patient sustains a SCI with delayed progressive deterioration in neurological function, in association with the MRI appearance of syringomyelia (SM), the diagnosis of PTSM is straightforward. The treatment of PTSM has not undergone any significant changes recently. The surgical treatment of PTSM consists of reconstructing the SAS or shunting fluid away from the syrinx to other locations. The advantages and disadvantages of each procedure will be discussed. With greater understanding of the mechanisms contributing to the development of SM, including advanced diagnostic methods and further advances in the development of artificial dural and shunting tubing, future therapies of PTSM will be more effective and long-lasting. Incorporation of alterations of AQP4 expression provides an intriguing possibility for future treatment of PTSM.

The future of spine surgery: New horizons in the treatment of spinal disorders

Background and Methods:

As with any evolving surgical discipline, it is difficult to predict the future of the practice and science of spine surgery. In the last decade, there have been dramatic developments in both the techniques as well as the tools employed in the delivery of better outcomes to patients undergoing such surgery. In this article, we explore four specific areas in spine surgery: namely the role of minimally invasive spine surgery; motion preservation; robotic-aided surgery and neuro-navigation; and the use of biological substances to reduce the number of traditional and revision spine surgeries.

Results:

Minimally invasive spine surgery has flourished in the last decade with an increasing amount of surgeries being performed for a wide variety of degenerative, traumatic, and neoplastic processes. Particular progress in the development of a direct lateral approach as well as improvement of tubular retractors has been achieved. Improvements in motion preservation techniques have led to a significant number of patients achieving arthroplasty where fusion was the only option previously. Important caveats to the indications for arthroplasty are discussed. Both robotics and neuro-navigation have become further refined as tools to assist in spine surgery and have been demonstrated to increase accuracy in spinal instrumentation placement. There has much debate and refinement in the use of biologically active agents to aid and augment function in spine surgery. Biological agents targeted to the intervertebral disc space could increase function and halt degeneration in this anatomical region.

Conclusions:

Great improvements have been achieved in developing better techniques and tools in spine surgery. It is envisaged that progress in the four focus areas discussed will lead to better outcomes and reduced burdens on the future of both our patients and the health care system.

Intraoperative neurophysiologic monitoring during syringomyelia surgery: lessons from a series of 13 patients

BACKGROUND

Avoiding iatrogenic neurological injury during spinal cord surgery is crucially important. Intraoperative neurological monitoring (INM) has been widely used in a variety of spinal surgeries as a means of reducing the risk of intraoperative neurological insults. This study evaluates the benefits of INM specifically in spinal procedures for treatment of syringomyelia.

METHODS

Thirteen patients who underwent surgery for syrinx drainage with the assistance of INM were included in this study. In all patients both somatosensory-evoked potentials (SSEP) and motor-evoked potentials (MEP) were monitored. INM data and perioperative neurological evaluations were both recorded and analyzed.

RESULTS

Eleven patients underwent syringo-subarachnoid shunt (SSAS) surgery. One patient underwent syrinx drainage and foramen magnum decompression (FMD). One patient underwent syringo-pleural shunt (SPA) surgery. Baseline MEP and SSEP were recordable at the beginning of surgery in 11 patients (>84 %). In the other two cases, baseline data from specific INM modalities were absent, correlating with the antecedent neurologic symptomotology. Two patients exhibited significant intraoperative changes in MEP data that influenced the course of surgery and prompted removal or re-insertion of the shunt. Mild and transient worsening of preoperative symptoms was reported in these instances. No new postoperative neurological deficits were reported in the other 11 patients in whom INM data were preserved throughout surgery.

CONCLUSION

These data support routine use of INM in syringomyelia surgery. INM can alert the surgeon to potential intraoperative threats to the functional integrity of the spinal cord, providing a useful adjunct to spinal cord surgeries for the treatment of syringomyelia.

Minimally invasive microscopically assisted lumbar discectomy using the METRx X-Tube system

BACKGROUND AND PURPOSE

Lumbar discectomy with the METRx X-Tube system and operating microscope is a modification of microendoscopic discectomy. The aim of this study was to describe this method and present the results of treatment of the first 13 patients.

MATERIAL AND METHODS

Under general anaesthesia and fluoroscopic guidance, a guidewire was placed over the inferior aspect of the superior lamina. A 2.5-3 cm midline skin incision was made, followed by paramedian lumbar fascia incision. Then, dilators were sequentially introduced (muscle-splitting approach). Finally, a tubular retractor was fixed directly over the interlaminar space. Further stages of the procedure were performed using an operating microscope and standard microdiscectomy equipment. The first 13 consecutive patients operated on using this method were analysed. Twelve patients were operated on at one level and 1 at two levels. Disc herniation was centro-lateral in 10 cases, lateral in 2 and central (broad-based) in 2 patients.

RESULTS

Regression of radicular pain was noted in all patients. No postoperative complications were observed except for prolongation of wound healing in 2 patients. According to mo-dified MacNab criteria, excellent late outcome was achieved in 8 patients and good in 4 patients. There were no cases of recurrent radicular pain or need for surgical revision for herniation recurrence. One patient was reoperated on because of low back pain (implantation of an interspinous spacer).

CONCLUSIONS

Microscopically assisted lumbar discectomy using the METRx X-Tube system seems to be safe and effective. This method combines the advantages of modern minimally invasive techniques while avoiding the limitations of endoscopy.