Incidence and management of cerebrospinal fluid fistulas in 336 multilevel laminectomies with noninstrumented fusions

Perspective: Operate on lumbar synovial cysts and avoid ineffective percutaneous techniques

Background

Lumbar synovial cysts (LSC), best diagnosed on MR studies, may cause symptoms/signs ranging from unilateral radiculopathy to cauda equina compressive syndromes. Attempts at percutaneous treatment of LSC typically fail. Rather, greater safety/efficacy is associated with direct surgical resection with/without fusion.

Methods

Treatment of LSC with percutaneous techniques, including cyst aspiration/perforation, injection (i.e., with/without steroids, saline/other), dilatation, and/or disruption/bursting, classically fail. This is because LSCs' tough, thickened, and adherent fibrous capsules cause extensive thecal sac/nerve root compression, and contain minimal central "fluid" (i.e., "crank-case" and non-aspirable). Multiple percutaneous attempts at decompression, therefore, typically cause several needle puncture sites risking dural tears (DT)/cerebrospinal fluid (CSF) leaks, direct root injuries, failure to decompress the thecal sac/nerve roots, infections, hematomas, and over the longer-term, adhesive arachnoiditis.

Results

Alternatively, many studies document the success of direct or even partial resection of LSC (i.e., partial removal with marked cyst/dural adhesions with shrinking down the remnant of capsular tissue). Surgical decompressions of LSC, ranging from focal laminotomies to laminectomies, may or may not warrant additional fusions.

Conclusions

Symptomatic LSC are best managed with direct or even partial operative resection/decompression with/without fusion. The use of varying percutaneous techniques classically fails, and increases multiple perioperative risks.

Perspective: Early direct repair of recurrent postoperative cerebrospinal (CSF) fluid leaks: No good evidence epidural blood patches (EBP) work

Background:

“Targeted” epidural blood patches (EBP)” successfully treat “focal dural tears (DT)” diagnosed on thin-cut MR or Myelo-CT studies. These DT are largely attributed to; epidural steroid injections (ESI), lumbar punctures (LP), spinal anesthesia (SA), or spontaneous intracranial hypotension (SICH). Here we asked whether “targeted EBP” could similarly treat MR/Myelo-CT documented recurrent post-surgical CSF leaks/DT that have classically been effectively managed with direct surgical repair.

Methods:

Utilizing ultrasound, fluoroscopy, or O-arm guidance, “targeted EBP” effectively manage “focal DT” attributed to ESI, LP, SA, or SICH. Here we reviewed the literature to determine whether similar “targeted EBP” could effectively manage recurrent postoperative CSF leaks/DT.

Results:

We were only able to identify 3 studies involving just 20 patients that attempted to utilize EBP to control postoperative CSF fistulas/DT. EBP controlled CSF fistulas/DT in 6 patients in the first study, and 9 of 10 patients (i.e. 90%: 2/2 cervical; 7/8 lumbar) in the second study. However, in the third study, 3 (60%) of 5 EBP failed to avert recurrent CSF leaks/DT in 4 patients (i.e. 1 cervical patient (2 EBP failed attempts), 3 lumbar patients (1 failed EBP)).

Conclusion:

Early direct surgical repair of recurrent postoperative spinal CSF leaks/DT remains the treatment of choice. Our literature review revealed 3 underpowered studies including just 20 patients where 20% of EBP failed to control recurrent postoperative fistulas (range of failure from 0-60% per study). Although there are likely other studies we failed to identify in this review, they too are likely insufficiently powered to document significant efficacy for performing EBP over direct surgical repair for recurrent postoperative CSF leaks/DT.

Unique Bone Suture Anchor Repair of Complex Lumbar Cerebrospinal Fluid Fistulas

Background

Spine surgeons encounter occasional complex cerebrospinal fluid fistulas/dural tears (CSF/DT) during lumbar spinal surgery. In some cases, these leaks are found during the index procedure, but others may appear postoperatively, or in the course of successive procedures. Here we asked, whether these complex CSF fistulas/DT could be more readily repaired utilizing a "bone suture anchor" technique, particularly where there is no residual dural margin/remnant.

Methods

With the combined expertise of the orthopedist and neurosurgeon, mini/micro bone suture anchors, largely developed for hand surgery, facilitated repair of complex DT occurring during lumbar spine surgery. This technique was utilized to suture in place fascia, periosteal, or muscle grafts, and was followed by the application of microfibrillar collagen, and a fibrin sealant.

Results

This mini/micro suture anchor technique has now been utilized to repair multiple significant intraoperative and/or postoperative recurrent DT, largely avoiding the need to place lumbar drains and/or lumbo- peritoneal shunts.

Conclusions

Here, we reviewed how to directly suture dural grafts utilizing a mini/micro bone suture anchor technique to repair complex intraoperative primary/recurrent DT occurring during lumbar spine surgery. The major advantages of this technique, in addition to obtaining definitive occlusion of the DT, largely avoids the need to place lumbar drains and/or lumbo-peritoneal shunts with their attendant risks and complications.

Diagnosis and Safe Excision of Lumbar Synovial Cysts and Accompanying Pathology: A Perspective

Background:

Lumbar synovial cysts are often not sufficiently diagnosed prior to spine surgery. Utilizing both MR and CT studies is critical for recognizing the full extent/severity of these lesions.

Methods:

In patients with chronic, acute, or subacute lumbar disease, obtaining both MR and CT studies is critical to correctly diagnose; disc disease, hypertrophy/ossification of the yellow ligament (OYL), stenosis, with/without degenerative spondylolisthesis, and/or synovial cysts (SC).

Results:

MR T2 weighted images directly demonstrate hyperintensity within a SC. They initially cause lateral recess/caudad nerve root and/foraminal compromise, with larger extrusions causing significant lateral thecal sac, and far lateral/superior cephalad root compromise. CT 2 mm cuts often better demonstrate mid-vertebral level compression of cephalad nerve roots with/without SC calcification, along with the extent of mid-vertebral stenosis, hypertrophy/OYL, and DS. When CT studies directly document SC calcification, it alerts the surgeon to the increased potential risk of creating a cerebrospinal fluid fistula with full SC excision, and should prompt the adoption of alternative measures such as decompression/partial removal. Most critically, surgery for synovial cysts often warrants a 2-level laminectomy for fuller visualization of the cephalad and caudad nerve roots, and clearer differentiation of neural tissues from the large fibrotic SC capsule, to effect safer removal.

Conclusions:

Preoperatively, establishing the full cephalad and cauda extent of lumbar synovial cysts with both MR and CT studies is critical. Anticipation and better visualization of the foraminal/far lateral and superior extent of these lesions often warrants more extensive multilevel laminectomies for thecal sac and both cephalad and caudad root decompression.