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Porche, Ken M.

0000-0002-2616-5853

Mayo Clinic

Mayo Clinic

Citations 9

Temporal evolution of tumefactive neurolymphomatosis with serial MRI and positron emission tomography: illustrative case
Porche, Ken , Amrami, Kimberly K. , Spinner, Robert J. , Porche, Ken M.

Journal of Neurosurgery: Case Lessons | May 18, 2026 | Volume: 11 | Issue: 20 | Pages: No page available

10.3171/case26139 Get It

BACKGROUND Neurolymphomatosis (NL), characterized by lymphoma infiltration of peripheral nerves, can be diagnostically challenging because of nonspecific clinical presentations and imaging findings. Tumefactive NL refers to circumferential subparaneurial tumor deposition beneath the paraneurium, outside the epineurium, producing an “encased” nerve appearance on MRI and at surgery. OBSERVATIONS A 76‑year‑old man with treated large B‑cell lymphoma developed a painful left lower trunk brachial plexopathy with numbness of the ring and little fingers and progressive weakness in finger flexors and intrinsic hand muscles. Serial brachial plexus MRI and 18F-fluorodeoxyglucose positron emission tomography over 4 months demonstrated evolution from a thin, circumferential subparaneurial rim of enhancement with mild nerve enlargement to a homogeneously enhancing, tumefactive lesion of the C8 nerve root and lower trunk. Targeted fascicular biopsy of a nonfunctioning C8 fascicle confirmed recurrent B‑cell lymphoma. LESSONS This case illustrates temporal evolution along the tumefactive NL spectrum, from early, subtle subparaneurial involvement to a frankly tumefactive lesion. Recognizing this early MRI pattern, particularly in patients with a history of lymphoma and focal plexopathy, can guide targeted biopsy and facilitate earlier diagnosis and treatment. The clinicoradiological findings suggest that subtle peripheral/subparaneurial enhancement may precede overt tumefactive enlargement. https://thejns.org/doi/10.3171/CASE26139
Baseline patient-reported outcome measures as predictors of postoperative dysphagia following anterior cervical spine surgery
Tippins, Nicholas P., Foreit, Anne M., Alentado, Vincent J. , Bisson, Erica F. , Foley, Kevin T. , Potts, Eric A. , Porche, Ken M.

Journal of Neurosurgery: Spine | November 17, 2025 | Volume: 44 | Issue: 1 | Pages: 30-44

10.3171/2025.6.spine25343 Get It

OBJECTIVE Patient-reported outcome measures (PROMs) are standardized questionnaires used to evaluate patients’ quality of life and health status before and after medical procedures. While worse preoperative health is often associated with worse postoperative outcomes, the role of baseline PROMs in predicting postoperative dysphagia following cervical surgery has been unexplored with Eating Assessment Tool–10 (EAT-10) scores. This study aimed to investigate the relationship between baseline PROMs and the incidence of postoperative dysphagia. METHODS A prospectively collected multi-institutional quality registry of patients undergoing anterior cervical spine surgery was retrospectively reviewed. Eight baseline PROMs were assessed: Neck Disability Index (NDI), modified Japanese Orthopaedic Association scale, EQ-5D questionnaire, EuroQol visual analog scale, visual analog scales for neck pain (NP-VAS) and arm pain, and 10-item Patient-Reported Outcomes Measurement Information System Global Physical Health and Global Mental Health. Including baseline dysphagia as a fixed effect, multivariable logistic regressions were performed to examine the impact of patient-reported baseline PROMs on the incidence of dysphagia. RESULTS Baseline PROMs were collected from 1706 patients. When assessing baseline PROMs independently in multivariable analyses, worse baseline NDI score (OR 1.04, p = 0.001) was a significant predictor of dysphagia at 12 months after surgery, while other PROMs were not. When assessing baseline PROMs together in multivariable analysis, worse baseline NDI score (OR 1.07, p < 0.001) and better NP-VAS score (OR 0.88, p = 0.006) were significant predictors of dysphagia at 12 months, while other PROMs were not. Patients in the severe or complete disability NDI categories (NDI score ≥ 25; 465/1466 patients without baseline dysphagia) experienced significantly more new dysphagia at 1 month (65% vs 50%, p < 0.001), 3 months (30% vs 21%, p < 0.001), and 12 months (32% vs 14%, p < 0.001) after anterior cervical spine surgery. These patients also had no significant difference in baseline EAT-10 scores (0.103 ± 0.386 vs 0.115 ± 0.405, p = 0.6), yet experienced significantly worse EAT-10 score changes between baseline and 12 months (3.369 ± 5.954 vs 1.208 ± 3.332, p < 0.001). CONCLUSIONS Baseline NDI score appears to be the strongest independent predictor of the 8 PROMs in determining whether patients have dysphagia at 12 months after anterior cervical surgery.
Impact of preoperative depression on postoperative dysphagia following cervical spine surgery
Tippins, Nicholas P., Foreit, Anne M., Alentado, Vincent J. , Bisson, Erica F. , Foley, Kevin T. , Potts, Eric A. , Porche, Ken M.

Journal of Neurosurgery: Spine | November 17, 2025 | Volume: 44 | Issue: 1 | Pages: 18-29

10.3171/2025.6.spine25342 Get It

OBJECTIVE This study examined the extent to which preoperative depression predicts dysphagia after cervical spine surgery. METHODS A prospectively collected multi-institutional quality registry was retrospectively reviewed. Patients undergoing cervical surgery were categorized based on preoperative depression, and correlations with pre- and postoperative Eating Assessment Tool-10 (EAT-10) dysphagia questionnaire scores were assessed. Mixed-effects logistic regressions were performed to assess the impact of preoperative depression on the incidence of dysphagia. RESULTS Of 2002 patients meeting inclusion criteria, 524 (26%) reported having preoperative depression. Depression was associated with a higher incidence of dysphagia at baseline (25% vs 12%, p < 0.001) and at 1 (62% vs 54%, p = 0.038), 3 (36% vs 26%, p < 0.001), and 12 months (36% vs 22%, p < 0.001) postoperatively. Including baseline dysphagia as a fixed effect, multivariable analysis revealed that depression is not a significant independent predictor of postoperative dysphagia at 1 (OR 1.14, p = 0.5), 3 (OR 1.09, p = 0.6), or 12 months (OR 1.27, p = 0.2). Patients with depression and no baseline dysphagia (395 of 524) were significantly more likely to report new dysphagia at 12 months (26% vs 18%, p = 0.006), but not at 1 (53% vs 52%, p = 0.7) or 3 months (28% vs 22%, p = 0.06). The average change in EAT-10 scores between baseline and 12 months was significantly worse in patients with preoperative depression and no baseline dysphagia (2.552 [SD 5.041] vs 1.634 [SD 4.095], p < 0.001). Post hoc multivariable analyses excluding those with baseline dysphagia did not significantly affect the results. CONCLUSIONS Although patients with preoperative depression report dysphagia more often at baseline and at 1, 3, and 12 months after cervical surgery, preoperative depression is not an independent predictor of postoperative dysphagia. Preoperative depression may be valuable to consider as a risk factor for developing dysphagia after cervical surgery, but the heightened dysphagia risk in patients with depression may be attributed to secondary factors associated with depression such as comorbid conditions.
Malignant peripheral nerve sheath tumors in schwannomatosis: a case series
Hayford, Kirsten M., Gui, Chloe , Suppiah, Suganth , Spinner, Robert J., Porche, Ken M. , Spinner, Robert J.

Journal of Neurosurgery | November 15, 2025 | Volume: 144 | Issue: 3 | Pages: 633-641

10.3171/2025.6.jns25872 Get It

OBJECTIVE Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas predominantly associated with neurofibromatosis type 1 (NF1). However, their occurrence within NF type 2 (NF2)–related and SMARCB1-related schwannomatosis remains rare and poorly characterized. Accurate and timely diagnosis is challenging due to clinical and radiological similarities with benign schwannomas, potentially delaying appropriate management and impacting outcomes. This study presents an institutional case series aiming to better characterize the clinical presentations specifically for MPNSTs arising in patients with NF2- and SMARCB1-related schwannomatosis. METHODS This retrospective case series included patients diagnosed with schwannomatosis who subsequently developed histopathologically confirmed MPNSTs. Conducted at Mayo Clinic (Rochester, Minnesota) and University Health Network (Toronto, Canada), the study spanned January 1, 2003, to November 1, 2024. Patients were selected based on clinical or genetic diagnoses of schwannomatosis using International Consensus Group on Neurofibromatosis Diagnostic Criteria. Comprehensive clinical, radiological, and pathological data, including demographics, presenting symptoms, tumor features (size, location, immunohistochemistry, genetics), treatments (resection, chemotherapy, radiotherapy), and follow-up outcomes were extracted from electronic medical records. RESULTS The authors identified 8 patients with a mean age of 36 years, half of whom had NF2-related schwannomatosis. The most common presenting symptom was pain (71%). The mean tumor size was 8.2 ± 7.0 cm, with gross-total resection being the most common surgical treatment (67%), typically supplemented with radiation therapy (78%). More than half of the patients (56%) exhibited metastatic disease, and all tumors with reported grading were Fédération Nationale des Centres de Lutte Contre le Cancer grade 3. No tumors were associated with LZTR1 mutations. One notable case involved a 39-year-old male with SMARCB1-related schwannomatosis who had a femoral MPNST resected 13 years prior and subsequently developed a sciatic nerve MPNST that was managed successfully with neoadjuvant chemotherapy, radiation therapy, and negative margin resection. Of note, the second lesion arose from a hybrid neurofibroma/schwannoma. Another case, a 33-year-old male with SMARCB1-related schwannomatosis, had an incidental finding of epithelioid MPNST in a minimally symptomatic small palmar lesion. CONCLUSIONS This case series highlights that MPNSTs, although uncommon, can arise in NF2- and SMARCB1-related schwannomatosis without prior radiation exposure, presenting significant diagnostic challenges due to their similarity to benign schwannomas. The findings underscore the importance of maintaining clinical vigilance and employing individualized management strategies, balancing thorough resection with the preservation of function and patient quality of life.
Malignant peripheral nerve sheath tumors in schwannomatosis: systematic review and meta-analysis
Hayford, Kirsten M., Gui, Chloe , Suppiah, Suganth , Spinner, Robert J., Porche, Ken M. , Spinner, Robert J.

Journal of Neurosurgery | November 15, 2025 | Volume: 144 | Issue: 3 | Pages: 642-652

10.3171/2025.6.jns251508 Get It

OBJECTIVE Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas commonly associated with neurofibromatosis type 1 (NF1), whose occurrence in schwannomatosis remains poorly understood. This study aimed to characterize MPNSTs in NF type 2 (NF2)– and SMARCB1-related schwannomatosis through a systematic review and meta-analysis of survival outcomes. METHODS A comprehensive search of the PubMed, Embase, Scopus, SEER (Surveillance, Epidemiology, and End Results), and Web of Science databases was conducted from database inception through January 2024. Clinical, radiological, histopathological, and treatment data were extracted. Primary endpoints included overall survival (OS) and progression-free survival (PFS). Predictors of outcomes were analyzed using Kaplan-Meier survival curves and Cox proportional hazards models. RESULTS A total of 39 cases were identified. NF2-related disease accounted for 67% of cases, while 28% were SMARCB1 related. The mean age at MPNST diagnosis was 33 years (range 9–79 years). Pain (41%) and weakness (26%) were the most common presenting symptoms. The mortality rate was 72.9%. No tumors were associated with LZTR1 mutations. Tumor locations varied widely, with involvement of the pelvis, thigh, skull base, forearm/hand, and cranial nerves. Trends suggested improved survival in the absence of S100 loss, gross-total resection, and a known schwannoma precursor. Conversely, having an intracranial or intraspinal lesion or having NF2 in the setting of prior radiation therapy were found to be associated with decreased survival and increased progression. A risk stratification tool predicted OS (HR 28.0, p < 0.0001) and PFS (HR 12.1, p < 0.0001). CONCLUSIONS MPNSTs, although rare in schwannomatosis, can arise even in the absence of prior radiation exposure and may mimic benign schwannomas. A preliminary risk stratification tool may aid in identifying high-risk patients and optimizing treatment approaches, although validation is needed. Given the aggressive nature of MPNSTs and their potential for delayed diagnosis due to their rarity, vigilant monitoring and individualized treatment strategies are crucial. Future research should focus on refining risk prediction models and exploring targeted therapies for schwannomatosis-associated MPNSTs to improve patient outcomes.
A comparative study on the effect of age on Neck Disability Index improvement at 24 months after surgical intervention for cervical spondylotic myelopathy: a Quality Outcomes Database study
Sherrod, Brandon A. , Rosero, Spencer , Chan, Andrew K. , Shaffrey, Christopher I., Gottfried, Oren N., Bydon, Mohamad , Asher, Anthony L. , Coric, Domagoj , Potts, Eric A. , Foley, Kevin T. , Wang, Michael Y. , Fu, Kai-Ming, Virk, Michael S. , Knightly, John J. , Meyer, Scott A., Upadhyaya, Cheerag D., Shaffrey, Mark E., Tumialán, Luis M. , Turner, Jay D. , Chou, Dean , Haid, Regis W., Mummaneni, Praveen V., Bisson, Erica F. , Porche, Ken M. , Shaffrey, Christopher I. , Fu, Kai-Ming, Uribe, Juan S. , Mummaneni, Praveen V. , Park, Paul

Journal of Neurosurgery: Spine | May 23, 2025 | Volume: 43 | Issue: 2 | Pages: 154-169

10.3171/2025.3.spine24598 Get It

OBJECTIVE Cervical spondylotic myelopathy (CSM) is often accompanied by neck pain, which, along with more recognized neurological deficits like motor and sensory changes, significantly impacts patients’ quality of life. The authors examined whether age influences improvements in neck disability and related quality-of-life measures after surgery for CSM. Using the Neck Disability Index (NDI) as the primary outcome, they compared long-term outcomes at 24 months among patients aged ≥ 65, ≥75, and < 65 years, exploring the effects of surgical intervention on both pain-related disability and functional recovery in older adults. METHODS Using the Quality Outcomes Database, the authors conducted a detailed propensity score–matched analysis on cohorts aged ≥ 65 and ≥ 75 years compared with a < 65-year-old cohort while controlling for baseline NDI scores, other demographic variables, health status, underlying pathology, number of levels, indication for surgery, surgical approach, and type of surgery. Differences in NDI total and subdomain scores at 24 months postoperatively were the primary measures of improvement. Age-related variability in NDI differential was assessed. EQ-5D and calculated SF-6D were secondary measures. RESULTS Of the 1141 patients in the cohort (January 2016 to December 2018), 687 patients were < 65 years, 325 were 65 to < 75 years, and 129 were ≥ 75 years of age. After propensity score matching, 197 patients each were well matched in the ≥ 65-year (mean 71.4 years) and < 65-year (mean 55.3 years) cohorts; similarly, 57 patients each were matched in the ≥ 75-year (mean 78.3 years) and < 65-year (mean 55.8 years) cohorts. Improvements in NDI scores and subdomain scores, EQ-5D, and calculated SF-6D were consistent at 3, 12, and 24 months postoperatively across all cohorts. At 24 months, patients ≥ 65 years showed NDI score improvements (−14.7 ± 22.3) similar to those < 65 years (−13.0 ± 21.3, p = 0.454), and patients ≥ 75 years demonstrated NDI improvements (−15.0 ± 19.7) comparable to those < 65 years (−17.6 ± 20.4, p = 0.499). A sensitivity analysis for linear relationship found that NDI improvement was statistically greater in older patients (7.5 points every 30 years, p < 0.0001), but this difference was below the minimal clinically important difference. Other clinical outcomes were similar between cohorts. CONCLUSIONS Surgical intervention for CSM yields substantial and similar improvements in NDI scores and other metrics among various age groups, including those aged at least 65 and 75 years. These results highlight the effectiveness of surgery across a broad patient demographic, underscoring its value in treating CSM irrespective of age.
Superficial peroneal to tibial nerve transfer for restoring plantar flexion in partial sciatic nerve injuries: illustrative case
Porche, Ken , Wu, Kitty Y. , Spinner, Robert J. , Porche, Ken M.

Journal of Neurosurgery: Case Lessons | March 25, 2025 | Volume: 9 | Issue: 12 | Pages: No page available

10.3171/case24888 Get It

BACKGROUND Peripheral nerve injuries in the lower extremities impose significant functional and quality-of-life challenges. Loss of plantar flexion is a major deficit. Novel nerve transfers are being introduced to restore function. A novel nerve transfer—partial superficial peroneal to a gastrocnemius branch of the tibial nerve—aimed at restoring plantar flexion is presented in a patient with an incomplete proximal thigh-level sciatic nerve injury. OBSERVATIONS The case of a 27-year-old policeman with a right sciatic nerve injury from a gunshot wound sustained 11 months earlier, characterized by intact dorsiflexion and eversion but with complete loss of plantar flexion and inversion, is presented. The patient underwent a nerve transfer from the superficial peroneal nerve to the lateral gastrocnemius branch of the tibial nerve at 10 months postinjury. At the 2-year follow-up, the patient achieved M4 strength in plantar flexion while maintaining M5 strength in ankle eversion, dorsiflexion, and toe extension, with ongoing signs of reinnervation to the lateral gastrocnemius on electromyography. LESSONS Partial transfer of the superficial peroneal nerve to the lateral gastrocnemius branch of the tibial nerve offers a promising solution for restoring plantar flexion in partial sciatic nerve injuries affecting the tibial division. Tailored distal nerve transfers can enhance recovery, underscoring the importance of surgical innovation in treating complex peripheral nerve injuries. https://thejns.org/doi/10.3171/CASE24888
Comparative analysis of patient-reported outcomes in myelopathy and myeloradiculopathy: a Quality Outcomes Database study
Bisson, Erica F. , Sherrod, Brandon A. , Dru, Alexander, Chan, Andrew K. , Shaffrey, Christopher I., Gottfried, Oren N., Bydon, Mohamad , Asher, Anthony L. , Coric, Domagoj , Potts, Eric A. , Foley, Kevin T. , Wang, Michael Y. , Fu, Kai-Ming, Virk, Michael S. , Knightly, John J. , Meyer, Scott A., Upadhyaya, Cheerag D., Shaffrey, Mark E., Tumialán, Luis M. , Turner, Jay D. , Chou, Dean , Haid, Regis W., Mummaneni, Praveen V., Porche, Ken M. , Shaffrey, Christopher I. , Fu, Kai-Ming, Uribe, Juan S. , Mummaneni, Praveen V. , Park, Paul

Journal of Neurosurgery: Spine | September 7, 2024 | Volume: 41 | Issue: 6 | Pages: 734-745

10.3171/2024.5.spine24170 Get It

OBJECTIVE Myelopathy in the cervical spine can present with diverse symptoms, many of which can be debilitating for patients. Patients with radiculopathy symptoms demonstrate added complexity because of the overlapping symptoms and treatment considerations. The authors sought to assess outcomes in patients with myelopathy presenting with or without concurrent radiculopathy. METHODS The Quality Outcomes Database, a prospectively collected multi-institutional database, was used to analyze demographic, clinical, and surgical variables of patients presenting with myelopathy or myeloradiculopathy as a result of degenerative pathology. Outcome measures included arm (VAS-arm) and neck (VAS-neck) visual analog scale (VAS) scores, modified Japanese Orthopaedic Association (mJOA) scale score, EuroQol VAS (EQ-VAS) score, and Neck Disability Index (NDI) at 3, 12, and 24 months compared with baseline. RESULTS A total of 1015 patients were included in the study: 289 patients with myelopathy alone (M0), 239 with myeloradiculopathy but no arm pain (MRAP−), and 487 patients with myeloradiculopathy and arm pain (MRAP+). M0 patients were older than the myeloradiculopathy cohorts combined (M0 64.2 vs MRAP− + MRAP+ 59.5 years, p < 0.001), whereas MRAP+ patients had higher BMI and a greater incidence of current smoking compared with the other cohorts. There were more anterior approaches used in in MRAP+ patients and more posterior approaches used in M0 patients. In severely myelopathic patients (mJOA scale score ≤ 10), posterior approaches were used more often for M0 (p < 0.0001) and MRAP+ (p < 0.0001) patients. Patients with myelopathy and myeloradiculopathy both exhibited significant improvement at 1 and 2 years across all outcome domains. The amount of improvement did not vary based on surgical approach. In comparing cohort outcomes, postoperative outcome differences were associated with patient-reported scores at baseline. CONCLUSIONS Patients with myelopathy and those with myeloradiculopathy demonstrated significant and similar improvement in arm and neck pain scores, myelopathy, disability, and quality of life at 3 months that was sustained at 1- and 2-year follow-up intervals. More radicular symptoms and arm pain increased the likelihood of a surgeon choosing an anterior approach, whereas more severe myelopathy increased the likelihood of approaching posteriorly. Surgical approach itself was not an independent predictor of outcome.
The effect of myelopathic symptoms on hospital costs, length of stay, and discharge location in anterior cervical discectomy and fusion
Vaziri, Sasha , Awan, Omar , Kubilis, Paul , Lipori, Paul, Hoh, Daniel J. , Polifka, Adam , Porche, Ken M. , Stein, Alan L. , Fox, W Christopher

Neurosurgical Focus | September 1, 2023 | Volume: 55 | Issue: 3 | Pages: E8

10.3171/2023.6.focus23288 Get It

OBJECTIVE Cervical spondylotic myelopathy (CSM) is a common clinical degenerative disease treated with anterior cervical discectomy and fusion (ACDF), which seriously impacts quality of life and causes severe disability. The objective of the study was to determine the effect of different characteristics of the neurological deficit found in myelopathic patients undergoing ACDFs on hospital cost, length of stay (LOS), and discharge location. METHODS This is a retrospective review of ACDF cases performed at a single institution by multiple surgeons from 2011 to 2017. Patient symptomatology, complications, comorbidities, demographics, surgical time, LOS, and discharge location were collected. Patients with readmissions or reoperations were excluded. Symptoms evaluated were based on clinical diagnosis, Japanese Orthopaedic Association classification, Ranawat grade, and Cooper scales. Symptoms were further grouped using principal component analysis. Cost was defined as surgical episode hospital stay costs plus outpatient clinic costs plus discharge disposition cost. Multivariate linear regression models were created to evaluate correlations with outcomes. The primary outcome was total 90-day hospital costs. Secondary outcomes were discharge location and LOS. RESULTS A total of 250 patients were included in the analyses. Discharge location, neuromonitoring use, number of surgical vertebral levels, cage use, LOS, surgical time, having a complication, and sex were all found to be predictive of total 90-day costs. Myelopathic symptomatology was not found to be associated with increased 90-day costs (p ≥ 0.131) when correcting for these other factors. Lower-extremity functionality was found to be associated with increased LOS (p < 0.0001). Upper-extremity myelopathy was found to be associated with increased discharge location needs (p < 0.0001). CONCLUSIONS Cervical myelopathy was not found to be predictive of total 90-day costs using symptomatology based on multiple myelopathy grading systems. Lower-extremity functionality was, however, found to predict LOS, while upper-extremity myelopathy was found to predict increased discharge location needs. This implies that preoperative deficits from myelopathy should not be considered in a bundled payment system; however, certain myelopathic symptoms should be considered when determining the cost of care.