Syringo-subarachnoid shunt: how I do it

Chiari Formation or Malformation? Trends in the Pathophysiology and Surgical Treatment of an Ever-Elusive Entity

Background: Chiari malformation type 1 (CM1) remains a complex neurosurgical condition with ongoing debate regarding its optimal management. Methods: This narrative review examines key controversies surrounding the pathophysiology, surgical indications, and treatment strategies for CM1. Results: We highlight the challenges posed by the wide spectrum of CM variants and the evolving understanding of its association with syringomyelia, basilar invagination, and craniovertebral instability. Emerging surgical techniques, including minimally invasive approaches and the use of new technologies such as endoscopes and exoscopes, are evaluated for their potential to improve outcomes. Recent consensus guidelines are also discussed. Conclusions: The need for individualized treatment plans for CM1 is emphasized, with special focus put on the connection between novel pathophysiological insights, technological advancements and opportunities for a more nuanced surgical management. Further research is necessary to establish solid foundations for more individualized treatments.

The cruciform drain: a technical note on the surgical management of cystic lesions of the sella

BACKGROUND

The postoperative recurrence of cystic lesions of the sella is frequent and may require further surgery for re-drainage.

OBJECTIVE

To tackle this problem, we propose to insert a small cross-shaped drain coursing from the cyst lumen to the suprasellar cistern. At this early stage of innovation, the technique is primarily intended for patients who present with a recurrence.

METHODS

The cruciform drain is fashioned from the tip of a ventricular catheter and is inserted under endoscopic vision. We retrospectively reviewed the pre- and postoperative records of patients in whom this technique was implemented.

RESULTS

A cruciform drain was placed in five patients since the introduction of the technique into our practice in 2018. The use of the cruciform drain did not impact upon the expected surgical workflow nor was it associated with adverse intraoperative events, but three patients did develop a postoperative CSF leak that was successfully treated in all cases. None of the patients showed re-collection of their cysts on early radiological follow-up.

CONCLUSION

The cruciform drain is intended to prevent the renewed build-up of cystic fluid by allowing it to flow through and around the drain into the subarachnoid space. We have modified our repair protocol in response to the observed high CSF leak rate, as a basis for further development of the technique. Studies involving long-term follow-up will also be required to assess its efficacy in reducing cyst recurrence.

Foramen magnum decompression with cervical syringotomy for Chiari malformation type I with syringomyelia - A useful adjunct in selected cases

Background

Persistent or worsening syringomyelia after foramen magnum decompression (FMD) for Chiari I malformation (CIM) can be challenging to manage. We present a previously unpublished surgical technique of FMD with concomitant cervical syringotomy in selected patients.

Methods

A retrospective analysis of prospectively collected data was carried out. Patients who underwent FMD and expansion duraplasty (FMDD) with concomitant syringotomy were collected.

Results

Three patients with CIM with high cervical syringomyelia who underwent FMDD with concurrent syringotomy were identified. All cases had an idiopathic CIM. Improvement in clinical symptoms was noticed in all patients. Early postoperative imaging (within 6 weeks-4 months) showed syrinx transverse diameter reduction in the range of 85-100%. There were no postoperative complications.

Conclusion

FMDD with concurrent high cervical syringotomy through a standard approach in selected cases of CIM with high cervical syringes achieves clinical improvement without additional complications.

Chiari Type 1 Malformation and Syringomyelia in Children: Classification and Treatment Options

Chiari type 1 malformation (CIM) is defined as tonsillar ectopia of >5 mm, while syringomyelia (SM) is defined as a cerebrospinal fluid (CSF)-filled cavity larger than 3 mm dissecting the spinal cord. Over the last decades, our understanding of these pathologies has grown; however, many controversies still exist almost in every aspect of CIM and SM, including etiology, indication for treatment, timing of treatment, surgical technique, follow-up regime, and outcome. This chapter provides a comprehensive overview on different aspects of CIM and SM and on the still existing controversies, based on the evidence presently available. Future directions for clinical research concerning CIM and SM treatment and outcome are elaborated and discussed as well.

A Clinical Study on the Treatment of Recurrent Chiari (Type I) Malformation with Syringomyelia Based on the Dynamics of Cerebrospinal Fluid

Objective. Combining the dynamics of cerebrospinal fluid, our study investigates the clinical effects of syringomyelia after the combination of fourth ventricle-subarachnoid shunt (FVSS) for recurrent Chiari (type I) malformations after cranial fossa decompression (foramen magnum decompression (FMD)). Methods. From December 2018 to December 2020, 15 patients with recurrent syringomyelia following posterior fossa decompression had FVSS surgery. Before and after the procedure, the clinical and imaging data of these individuals were retrospectively examined. Results. Following FVSS, none of the 15 patients experienced infection, nerve injury, shunt loss, or obstruction. 13 patients improved dramatically after surgery, while 2 patients improved significantly in the early postoperative period, but the primary symptoms returned 2 months later. The Japanese Orthopedic Association (JOA) score was $12.67\pm 3.95$ , which was considerably better than preoperatively ( $t=3.69$ , $P$ 0.001). The MRI results revealed that the cavities in 13 patients were reduced by at least 50% compared to the cavities measured preoperatively. The shrinkage rate of syringomyelia was 86.67% (13/15). One patient’s cavities nearly vanished following syringomyelia. The size of the cavity in the patient remain unchanged, and the cavity’s maximal diameter was significantly smaller than the size measured preoperatively ( $P<0.001$ ) PC-MRI results indicated that the peak flow rate of cerebrospinal fluid at the central segment of the midbrain aqueduct and the foramen magnum in patients during systole and diastole were significantly reduced after surgery ( $P<0.05$ ). Conclusion. After posterior fossa decompression, FVSS can effectively restore the smooth circulation of cerebrospinal fluid and alleviate clinical symptoms in patients with recurrent Chiari (type I) malformation and syringomyelia. It is a highly effective way of treatment.

The Management of Idiopathic and Refractory Syringomyelia

Idiopathic syringomyelia (IS) and refractory syringomyelia (RS) are types of syringomyelia that often pose a management challenge and are associated with long-term clinical sequela. They are usually an epiphenomenon reflecting an underlying pathology where the treatment of the primary cause should be the aim for any surgical intervention. In the case of IS, the initial step is agreeing on the definition of the terms idiopathic and syringomyelia. After a rigorous exhaustive clinic-radiological workup, only IS patients with progressive neurology are treated, usually unblocking subarachnoid cerebrospinal fluid (CSF) pathway obstruction somewhere in the thoracic spinal canal and reserving shunting techniques to nonresponsive cases. Similar to IS, also RS is multifactorial, and its management varies based on the initial pathology, strongly supported by radiological and clinical features. We aim to address this topic focusing on the etiopathology, investigation paradigm, and surgical pathway, formulating algorithms of management with available evidence in literature. Surgical techniques are discussed in detail.

Syringomyelia and hydromyelia: Current understanding and neurosurgical management

Syringomyelia is a rare disorder in which a fluid-filled cyst forms within the spinal cord, resulting in myelopathy. Meanwhile, the abnormal dilatation of the central canal is referred to as hydromyelia or slit-like syrinx. The most prevailing classification is based on anatomical features and pathogeny rather than pathophysiological mechanisms. It is usual to distinguish foraminal syringomyelia related mainly to abnormalities at the craniocervical junction, non-foraminal syringomyelia dealing with any cause of arachnoiditis (infection, inflammation, trauma…) and more rarely syringomyelia associated with intramedullary tumors. Although many pathophysiological theories have been argued over time, the prevailing one is that disturbances in cerebrospinal fluid (CSF) flow in the sub-arachnoid spaces disrupt flow velocity leading to the syrinx. Symptoms of paralysis, sensory loss and chronic pain commonly develop during the third/fourth decades of life. The natural history of syringomyelia is typically one of gradual, stepwise neurological deterioration extending over many years. Diagnosis is based on magnetic resonance imaging (MRI) including excellent morphological sequences (T1-, T2-, FLAIR-, T2*-, enhanced T1-) and dynamic MRI with careful study of CSF velocity (CISS, cine-MR sequences). Surgical management is at first dedicated to treat the cause of the syringomyelia, mainly to re-establish a physiological CSF pathway in the subarachnoid spaces. Mostly, the surgical goal is to enlarge the craniocervical junction with duraplasty. Other surgical strategies such as arachnoidolysis or shunt procedures are performed based on the pathogenic mechanisms or as second-line treatment. Medical treatments are also necessary as chronic pain is the main long-lasting symptom. As evolutive syringomyelia is a severe disease with a high impact on quality of life, it is recommended to treat without delay. There is no evidence for surgery for incidental asymptomatic syringomyelia or hydromyelia. Finally, syringomyelia associated with intramedullary tumors resolves spontaneously after tumor resection. Syringomyelia is a rare disease, which requires a dedicated multidisciplinary approach, emphasizing the need for a nationwide scientific organization so as to offer optimal care to the patient.

Risk factors of unplanned neurosurgery for scoliotic patients with Chiari malformation type I and syringomyelia after spinal deformity correction

OBJECTIVES

It remains unclear which subgroups of scoliotic patients with CMI and syringomyelia are more likely to undergo unplanned neurosurgery after spinal deformity correction. The purpose of this study is to explore risk factors of unplanned neurosurgery for scoliotic patients with CMI and syringomyelia after spinal deformity correction.

PATIENTS AND METHODS

This cohort consisted of 62 scoliotic patients with CMI and syringomyelia who underwent spinal deformity surgery with a mean follow-up of 4.3 year. 14 of them underwent unplanned neurosurgery (the NN group), and the other 48 patient underwent single spinal correction surgery (the SS group). The radiological parameters were compared between the two groups, and multivariate logistic regression analysis and Kaplan-Meyer survival curves were used to identify potential risk factors of unplanned neurosurgery.

RESULTS

The incidence of unplanned neurosurgery after spinal deformity surgery was 22.28 % (14/62), and delayed headache was the most common reason for unplanned neurosurgery with five patients (36 %) and follow by neck pain with three patients (21 %). Significantly increased tonsil ectopia (9.7 ± 3.8 vs. 6.9 ± 2.9; P = 0.021), syrinx/cord width ratio (0.62±0.11 vs. 0.45±0.13; P＜0.001), and syrinx/cord area ratio (0.45 ± 0.11 vs. 0.26 ± 0.15; P＜0.001) were found in the NN group. While, there were no significant differents in pBC2 line, clivus canal angle, and syrinx length between the two groups. The logistic regression analysis indicated that tonsil ectopia≥10 mm (P = 0.019; OR=6.440; 95 %CI = 1.361 to 30.467) and syrinx/cord area ratio ≥ 0.4 (P = 0.006; OR=7.664; 95 %CI = 1.819 to 32.291) were independent risk factors of unplanned neurosurgery. Kaplan-Meyer survival curves showed cumulative unplanned neurosurgery for patients with tonsil ectopia ≥ 10 mm (P < 0.001) and syrinx/cord area ratio ≥ 0.4 (P = 0.001) after spinal deformity correction.

CONCLUSION

After spinal deformity correction, 78 % of the patients did not require later neurosurgery and those that needed it had a delay of more than nine months. Tonsil ectopia ≥ 10 mm and syrinx/cord area ratio ≥ 0.4 were independent risk factor of unplanned neurosurgery after spinal deformity correction. It is reasonable to perform spinal corrective surgery in patients with minimal symptoms and signs without the need for prior neurosurgical intervention.

MINIMALLY INVASIVE TREATMENT OF IDIOPATHIC SYRINGOMYELIA USING MYRINGOTOMY T-TUBES: A CASE REPORT AND TECHNICAL NOTE

Syringomyelia is characterized by a fluid-filled cavity within the spinal cord. Expansion of the syrinx often results in the clinical course of progressive neurologic deficit. Surgery for syringomyelia generally aims to treat the underlying cause, if it is known. However, little is known about idiopathic syringomyelia, which requires specific management. In our paper, an alternative, minimally invasive treatment option for large symptomatic idiopathic cervicothoracic syrinx is described and discussed. We present a case of a 44-year-old male without a history of spinal cord trauma, infection, or other pathologic processes, who presented for thoracic pain. Due to progressive pain and left leg paresis, magnetic resonance imaging (MRI) was performed and revealed extensive septated syringomyelia from T5 to T7 and hydromyelia cranially. We applied minimally invasive technique for shunting the idiopathic syrinx into the subarachnoid space using two Richards modified myringotomy T-tubes. Postoperative MRI revealed significant decrease in the syrinx size and clinical six-month follow-up showed improvement of clinical symptoms. This minimally invasive treatment of syringomyelia was found to be an effective method for idiopathic septated syrinx, without evident underlying cause. However, long-term follow-up and more patients are necessary for definitive evaluation of this technique.

Direct syrinx drainage in patients with Chiari I malformation

While FMD is, to date, the primary treatment of symptomatic CM I, the treatment of Chiari malformation type I (CM I) associated syrinx remains controversial. In cases of persistent, progressive, or recurrent syrinx following FMD, direct syrinx drainage (DSD) is described as a safe and efficient option, leading to a good clinical and radiological outcome. However, studies at hand mostly include very heterogeneous patient populations, small cohorts, and are of retrospective nature. We provide an overview of the possible indications and outcome for DSD in CM I-associated syrinx. We discuss the different surgical techniques of DSD and review the available literature comparing different DSD techniques. Finally, we discuss the possible complications that might occur after DSD and how they can be prevented.