Need for arthrodesis following facetectomy for spinal peripheral nerve sheath tumors: an institutional experience and review of the current literature

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OBJECTIVE

Spinal peripheral nerve sheath tumors (PNSTs) are a group of rare tumors originating from the nerve and its supporting structures. Standard surgical management typically entails laminectomy with or without facetectomy to gain adequate tumor exposure. Arthrodesis is occasionally performed to maintain spinal stability and mitigate the risk of postoperative deformity, pain, or neurological deficit. However, the factors associated with the need for instrumentation in addition to PNST resection in the same setting remain unclear.

METHODS

An institutional tumor registry at a tertiary care center was queried for patients treated surgically for a primary diagnosis of spinal PNST between 2002 and 2016. An analysis focused on patients in whom a facetectomy was performed during the resection. The addition of arthrodesis at the index procedure comprised the primary outcome. The authors also recorded baseline demographics, tumor characteristics, and surgery-related variables. Logistic regression was used to identify factors associated with increased risk of fusion surgery.

RESULTS

A total of 163 patients were identified, of which 56 (32 had facetectomy with fusion, 24 had facetectomy alone) were analyzed. The median age was 48 years, and 50% of the cohort was female. Age, sex, and race, as well as tumor histology and size, were evenly distributed between patients who received facetectomy alone and those who had facetectomy and fusion. On univariate analysis, total versus subtotal facetectomy (OR 9.0, 95% CI 2.01–64.2; p = 0.009) and cervicothoracic versus other spinal region (OR 9.0, 95% CI 1.51–172.9; p = 0.048) were significantly associated with increased odds of performing immediate fusion. On multivariable analysis, only the effect of total facetectomy remained statistically significant (OR 6.75, 95% CI 1.47–48.8; p = 0.025).

CONCLUSIONS

The authors found that total facetectomy and cervicothoracic involvement may be highly associated with the need for concomitant arthrodesis at the time of index surgery. These findings may help surgeons to determine the best surgical planning for patients with PNST.

ABBREVIATIONS GTR = gross-total resection; IQR = interquartile range; NF1 = neurofibromatosis type 1; PNST = peripheral nerve sheath tumor; PRISMA = Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

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Article Information

Correspondence Mohamad Bydon: Mayo Clinic, Rochester, MN. bydon.mohamad@mayo.edu.

INCLUDE WHEN CITING Published online April 5, 2019; DOI: 10.3171/2019.1.SPINE181057.

Disclosures Dr. Yoon has an ownership interest in MedCyclops, LLC.

© AANS, except where prohibited by US copyright law.

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    A 55-year-old woman presented with new-onset, left-sided, low-back pain that radiated to the anterolateral left hip, thigh, and groin. The pain would come on at night while she was in bed or with jarring motions of the Valsalva maneuver and going from a standing to a sitting position. No neurological findings were noted in the physical examination. MRI of the lumbar spine revealed a well-circumscribed, enhancing, T1 isointense, T2 hyperintense, intradural, extramedullary mass at the L1–2 level, suggestive of a diagnosis of schwannoma. The lesion measured 1.7 × 1.7 × 1.9 cm (anteroposterior by left-right by superior-inferior), and resulted in left-to-right compression of the conus and subjacent nerve roots. The patient underwent L1–2 laminectomy. Postoperative MRI showed successful complete resection of the tumor.

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    A 42-year-old woman presented with a 3-year history of gradually developing numbness and pain in the right ulnar side of the hand. On physical examination she was noted to have mild weakness affecting both median and ulnar extrinsic and intrinsic muscles. Her electromyogram showed moderately severe right C8 radiculopathy with involvement of the dorsal root ganglion. MRI revealed expansion of the right C7 neural foramen by a 31 × 14–mm extradural mass, consistent with schwannoma or neurofibroma. The tumor projected into the central spinal canal and displaced the spinal cord but did not compress it. No other spinal tumors were identified. A decision was made to proceed with right C7–T1 hemilaminectomy, right total C7–T1 facetectomy, and C6–T2 fusion with lateral mass and pedicle screws.

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    A 29-year-old man underwent left L2–3 laminectomy, total facetectomy, and severance of the left L2 nerve root for resection of melanocytic schwannoma. Three years later the tumor demonstrated mild interval growth, abutting the lower left L1 pedicle, enlarging the foramen with slightly increased compression of the thecal sac on the left and slightly increased thickness of its extraforaminal portion. A decision was made to proceed with complete L2–3 laminectomy, L2 corpectomy, L1–3 nerve root ligation, and T12–L4 posterior instrumented fusion to achieve GTR of the tumor.

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    Results of our electronic search strategy according to the PRISMA guidelines. Figure is available in color online only.

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