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Dive into the research topics where Zachary S. Mendelson is active.

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Featured researches published by Zachary S. Mendelson.


World Neurosurgery | 2014

Endoscopic Versus Microsurgical Resection of Colloid Cysts: A Systematic Review and Meta-Analysis of 1278 Patients

Ahmed B. Sheikh; Zachary S. Mendelson; James K. Liu

OBJECTIVE Colloid cysts of the third ventricle have been successfully treated with transcranial microsurgical approaches. However, the endoscopic approach has recently been advocated as a lesser invasive technique. We conducted a systematic review and meta-analysis of published studies to compare the outcomes between the two approaches. METHODS A PubMED search of contemporary literature (1990-2014) was performed to identify surgical series of open and endoscopic treatment of colloid cysts. Relevant articles were identified and data were extracted concerning surgical treatment, extent of resection, and outcomes. RESULTS A meta-analysis was performed for recurrence rates based on treatment strategy. A total of 583 patients were included in the microsurgical group, and 695 patients in the endoscopic group. The microsurgical approach was found to have a significantly higher gross total resection rate (96.8% vs. 58.2%; P < 0.0001), lower recurrence rate (1.48% vs. 3.91%; P = 0.0003), and lower reoperation rate (0.38% vs. 3.0%; P = 0.0006) compared with the endoscopic group. There was no significant difference in mortality rate (1.4% vs. 0.6%) or shunt dependency (6.2% vs. 3.9%) between the two groups. The overall morbidity rate was lower in the endoscopic group (10.5%) than in the microsurgery group (16.3%). Within the microsurgery group, the transcallosal approach had a lower overall morbidity rate (14.4%) than the transcortical approach (24.5%). CONCLUSIONS Microsurgical resection of colloid cysts is associated with a higher rate of complete resection, lower rate of recurrence, and fewer reoperations than with endoscopic removal. However, the rate of morbidity is higher with microsurgery than with endoscopy.


Journal of Clinical Neuroscience | 2014

Rathke's cleft cyst recurrence after transsphenoidal surgery: A meta-analysis of 1151 cases

Zachary S. Mendelson; Qasim Husain; Sedeek Elmoursi; Peter F. Svider; Jean Anderson Eloy; James K. Liu

Rathkes cleft cysts (RCC) arise from the development of the Rathkes cleft pouch. These commonly occurring cysts are typically asymptomatic, but sometimes present with headaches, endocrine dysfunction, and visual loss. Recurrence is common after either drainage or surgical removal. The purpose of this study was to review published outcomes for RCC management, and determine whether specific factors, including patient demographics, cyst pathology, radiologic parameters, or surgical techniques predispose to their recurrence. A systematic review of studies for RCC from 1990 to 2012 was conducted. Patients were identified using a Medline/PubMed search, and from the bibliographies of relevant articles obtained from the primary search. Relevant studies reporting recurrence rate were identified, and data were extracted regarding patient demographics, presenting symptoms, cyst characteristics, surgical treatment, and outcomes. A meta-analysis for recurrence rates was also performed. Twenty-eight journal articles comprising a total of 1151 RCC revealed an average follow-up of 38 months (range 16-79 months). In the studies reviewed, there was a relatively equal distribution of treatment approaches, with 35% subtotal resection, 33% gross total resection, and 32% complete drainage with wall biopsy. The microsurgical transsphenoidal approach was found to have a higher recurrence rate (14% versus 8%) and new endocrine dysfunction rate (25% versus 10%) compared to the endoscopic approach. The data demonstrates a notable overall recurrence rate for RCC (12.5%). However, there appears to be no conclusive evidence that more aggressive resection of the cyst wall results in lower rates of recurrence.


Journal of Neurosurgery | 2016

Endoscopic graduated multiangle, multicorridor resection of juvenile nasopharyngeal angiofibroma: an individualized, tailored, multicorridor skull base approach

James K. Liu; Qasim Husain; Kanumuri; Mohemmed N. Khan; Zachary S. Mendelson; Jean Anderson Eloy

OBJECT Juvenile nasopharyngeal angiofibromas (JNAs) are formidable tumors because of their hypervascularity and difficult location in the skull base. Traditional transfacial procedures do not always afford optimal visualization and illumination, resulting in significant morbidity and poor cosmesis. The advent of endoscopic procedures has allowed for resection of JNAs with greater surgical freedom and decreased incidence of facial deformity and scarring. METHODS This report describes a graduated multiangle, multicorridor, endoscopic approach to JNAs that is illustrated in 4 patients, each with a different tumor location and extent. Four different surgical corridors in varying combinations were used to resect JNAs, based on tumor size and location, including an ipsilateral endonasal approach (uninostril); a contralateral, transseptal approach (binostril); a sublabial, transmaxillary Caldwell-Luc approach; and an orbitozygomatic, extradural, transcavernous, infratemporal fossa approach (transcranial). One patient underwent resection via an ipsilateral endonasal uninostril approach (Corridor 1) only. One patient underwent a binostril approach that included an additional contralateral transseptal approach (Corridors 1 and 2). One patient underwent a binostril approach with an additional sublabial Caldwell-Luc approach for lateral extension in the infratemporal fossa (Corridors 1-3). One patient underwent a combined transcranial and endoscopic endonasal/sublabial Caldwell-Luc approach (Corridors 1-4) for an extensive JNA involving both the lateral infratemporal fossa and cavernous sinus. RESULTS A graduated multiangle, multicorridor approach was used in a stepwise fashion to allow for maximal surgical exposure and maneuverability for resection of JNAs. Gross-total resection was achieved in all 4 patients. One patient had a postoperative CSF leak that was successfully repaired endoscopically. One patient had a delayed local recurrence that was successfully resected endoscopically. There were no vascular complications. CONCLUSIONS An individualized, multiangle, multicorridor approach allows for safe and effective surgical customization of access for resection of JNAs depending on the size and exact location of the tumor. Combining the endoscopic endonasal approach with a transcranial approach via an orbitozygomatic, extradural, transcavernous approach may be considered in giant extensive JNAs that have intracranial extension and intimate involvement of the cavernous sinus.


British Journal of Neurosurgery | 2015

Endoscopic palliative decompression of the cavernous sinus in a rare case of a metastatic renal cell carcinoma to the clivus.

Zachary S. Mendelson; Amit A. Patel; Jean Anderson Eloy; James K. Liu

Abstract We present a rare case of acute cavernous sinus syndrome due to a renal cell carcinoma metastasis to the clivus. This case highlights the role of palliative endoscopic endonasal decompression of the cavernous sinus to relieve cranial neuropathies, obtain tissue diagnosis, and for cytoreduction in preparation for additional adjuvant therapy.


Laryngoscope | 2015

Endoscopic ventral skull base surgery: Is early postoperative imaging warranted for detecting complications?

Lucia Diaz; Leila J. Mady; Zachary S. Mendelson; James K. Liu; Jean Anderson Eloy

Following endoscopic ventral skull base surgery (EVSBS), it is common practice to obtain early postoperative imaging. The role of postoperative computed tomography (CT) and magnetic resonance imaging (MRI) scans in these patients remains unclear. This study aims to determine the clinical utility of early postoperative imaging after EVSBS for detecting postoperative complications.


Journal of Clinical Neuroscience | 2016

Fat graft-assisted internal auditory canal closure after retrosigmoid transmeatal resection of acoustic neuroma: Technique for prevention of cerebrospinal fluid leakage

Tareq Azad; Zachary S. Mendelson; Anni Wong; Robert W. Jyung; James K. Liu

The retrosigmoid transmeatal approach remains an important strategy in the surgical management of acoustic neuromas. Gross total resection of acoustic neuromas requires removal of tumor within the cerebellopontine angle as well as tumor involving the internal auditory canal (IAC). Drilling into the petrous bone of the IAC can expose petrous air cells, which can potentially result in a fistulous tract to the nasopharynx manifesting as cerebrospinal fluid (CSF) rhinorrhea. We describe our method of IAC closure using autologous fat graft and assessed the rates of postoperative CSF leakage. We performed a retrospective study of 24 consecutive patients who underwent retrosigmoid transmeatal resection of acoustic neuroma who underwent our method of fat graft-assisted IAC closure. We assessed rates of postoperative CSF leak (incisional leak, rhinorrhea, or otorrhea), pseudomeningocele formation, and occurrence of meningitis. Twenty-four patients (10 males, 14 females) with a mean age of 47 years (range 18-84) underwent fat graft-assisted IAC closure. No lumbar drains were used postoperatively. There were no instances of postoperative CSF leak (incisional leak, rhinorrhea, or otorrhea), pseudomeningocele formation, or occurrence of meningitis. There were no graft site complications. Our results demonstrate that autologous fat grafts provide a safe and effective method of IAC defect closure to prevent postoperative CSF leakage after acoustic tumor removal via a retrosigmoid transmeatal approach. The surgical technique and operative nuances are described.


Journal of Clinical Neuroscience | 2015

Endoscopic transsphenoidal surgery of Rathke's cleft cyst

Zachary S. Mendelson; Qasim Husain; Vivek V. Kanumuri; Jean Anderson Eloy; James K. Liu

Rathkes cleft cysts (RCC) are benign lesions that originate from remnants of Rathkes pouch. They can compress adjacent structures causing visual loss and endocrine dysfunction. The endoscopic endonasal transsphenoidal approach (EETA) has gained popularity in the surgical management of pituitary and parasellar tumors. However, postoperative cyst recurrence and endocrine dysfunction are still major concerns. A retrospective chart review was performed on 11 patients who underwent a purely EETA. Subtotal resection of the cyst wall with drainage of the intracystic contents followed by obliteration of the cyst with a fat graft was performed in all patients. Two patients underwent repeated surgeries for symptomatic cyst recurrence. One patient ultimately underwent extracapsular removal of the entire cyst wall because of multiple recurrences after simple drainage. There were no incidences of new permanent hypopituitarism, visual deficits, or postoperative cerebrospinal fluid leaks. All patients reported an improvement of initial preoperative symptoms. A non-aggressive strategy of partial cyst wall removal and simple drainage of cyst contents via EETA is a viable approach for surgical treatment of RCC with a low rate of postoperative endocrine and visual complications. A more aggressive strategy of extracapsular removal of the cyst wall may be indicated in patients with repeated recurrence.


World Neurosurgery | 2018

Relaxing Sphenoidal Slit Incision to Extend the Anterior and Posterior Reach of Pedicled Nasoseptal Flaps During Endoscopic Skull Base Reconstruction of Transcribriform Defects: Technical Note and Results in 20 Patients

James K. Liu; Zachary S. Mendelson; Gurkirat Kohli; Jean Anderson Eloy

BACKGROUND Reconstruction of large anterior skull base (ASB) defects after an endoscopic endonasal transcribriform approach (EEA-TC) remains a challenge despite the advent of the vascularized pedicled nasoseptal flap (PNSF). OBJECTIVE We describe a relaxing PNSF slit incision that extends the anterior and posterior reach of the PNSF to maximize tensionless flap coverage of transcribriform ASB defects. METHODS A retrospective chart review was conducted on 20 consecutive patients who underwent endoscopic endonasal transcribriform approach and subsequent PNSF reconstruction with a relaxing slit incision. At the time of endoscopic ASB reconstruction, the PNSF is rotated into position so that the anterior margin of the flap is situated at the posterior table of the frontal sinus. A relaxing slit incision is made across the sphenoidal segment of the PNSF, which is the segment of flap that bridges across the sphenoid sinus once the flap is rotated into position. The anterior reach of the flap is increased to adequately cover the posterior table of the frontal sinus, and the redundant sphenoidal flap is rotated posteriorly to make contact to the bony planum sphenoidale. RESULTS No patients developed postoperative cerebrospinal fluid leaks (0%). The ASB repair was monitored via postoperative outpatient nasal endoscopy at various time points, which demonstrated excellent mucosalization of the ASB with a mean follow-up of 19.2 months (range: 4.1-36.2 months). CONCLUSIONS Our simple relaxing slit incision in the sphenoidal portion of the PNSF allows for maximal tensionless coverage of extensive transcribriform defects by increasing the anterior and posterior reach of the flap.


Skull Base Surgery | 2015

Retractorless Microvascular Decompression for Trigeminal Neuralgia: Technical Nuances and Results in 25 Cases

James K. Liu; Zachary S. Mendelson; Ahmed B. Sheikh; Gary M. Heir

Introduction: Operative microsurgery of skull base lesions without the use of fixed retractors has gained increased popularity because of less morbidity and brain injury from retractor-induced complications. In microvascular decompression procedures, cerebellar retraction can increase the risk of postoperative hearing loss and cerebellar injury. The authors present a series of patients with trigeminal neuralgia (TN) who underwent a retractorless microvascular decompression (RMVD). The operative nuances and technical pearls are described and assessment of pain relief and postoperative complications are reported. Methods: A retrospective chart review was performed on 23 patients diagnosed with TN. All patients were treated by way of RMVD through a retrosigmoid approach. Data were extracted regarding patient demographics, presenting symptoms, affected trigeminal branches, intraoperative and postoperative complications, degree of pain relief (based on BNI pain scale), and pain recurrence. Results: A total of 23 patients (15 females and 8 males) underwent 25 RMVD procedures. One patient had bilateral procedures and one patient had a repeat RMVD for pain free recurrence. There were no complications of hearing loss, facial palsy, trigeminal dysfunction, radiographic or clinical cerebellar injury, or CSF leakage. There were 21 (84%) initial BNI grade I outcomes defined by being completely pain free and not taking medication. There were two “pain free recurrences” defined as initially being scored as BNI grade I for longer than 3 months and then experiencing recurrent symptoms of TN. One patient underwent repeat RMVD and improved to BNI grade I, and the other patient underwent radiosurgery and was lost to follow-up. Three patients had a BNI grade II outcome defined by significant but not total pain relief without the use of medication. One patient was considered a BNI grade V outcome defined by persistent pain with medication use. On final outcome, 18 patients (91%) achieved a BNI grade I–II (78% grade I, 13% grade II), 3 (13%) BNI grade II, 1 (4%) “pain-free recurrence,” and 1 (4%) BNI grade V. Conclusion: RMVD is a safe and effective strategy for surgical treatment of TN. The avoidance of fixed retractors can minimize the risk of postoperative hearing loss and cerebellar injury.


Journal of Clinical Neuroscience | 2014

The modified hemi-Lothrop procedure: A variation of the endoscopic endonasal approach for resection of a supraorbital psammomatoid ossifying fibroma

James K. Liu; Zachary S. Mendelson; Pariket M. Dubal; Neena Mirani; Jean Anderson Eloy

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James K. Liu

Case Western Reserve University

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