Mayank Kaushal and Shekar N. Kurpad
Zachary C. Gersey, S. Shelby Burks, Kim D. Anderson, Marine Dididze, Aisha Khan, W. Dalton Dietrich, and Allan D. Levi
Long-segment injuries to large peripheral nerves present a challenge to surgeons because insufficient donor tissue limits repair. Multiple supplemental approaches have been investigated, including the use of Schwann cells (SCs). The authors present the first 2 cases using autologous SCs to supplement a peripheral nerve graft repair in humans with long-term follow-up data.
Two patients were enrolled in an FDA-approved trial to assess the safety of using expanded populations of autologous SCs to supplement the repair of long-segment injuries to the sciatic nerve. The mechanism of injury included a boat propeller and a gunshot wound. The SCs were obtained from both the sural nerve and damaged sciatic nerve stump. The SCs were expanded and purified in culture by using heregulin β1 and forskolin. Repair was performed with sural nerve grafts, SCs in suspension, and a Duragen graft to house the construct. Follow-up was 36 and 12 months for the patients in Cases 1 and 2, respectively.
The patient in Case 1 had a boat propeller injury with complete transection of both sciatic divisions at midthigh. The graft length was approximately 7.5 cm. In the postoperative period the patient regained motor function (Medical Research Council [MRC] Grade 5/5) in the tibial distribution, with partial function in peroneal distribution (MRC Grade 2/5 on dorsiflexion). Partial return of sensory function was also achieved, and neuropathic pain was completely resolved. The patient in Case 2 sustained a gunshot wound to the leg, with partial disruption of the tibial division of the sciatic nerve at the midthigh. The graft length was 5 cm. Postoperatively the patient regained complete motor function of the tibial nerve, with partial return of sensation. Long-term follow-up with both MRI and ultrasound demonstrated nerve graft continuity and the absence of tumor formation at the repair site.
Presented here are the first 2 cases in which autologous SCs were used to supplement human peripheral nerve repair in long-segment injury. Both patients had significant improvement in both motor and sensory function with correlative imaging. This study demonstrates preliminary safety and efficacy of SC transplantation for peripheral nerve repair.
Kyle Juraschka, Osaama H. Khan, Bruno L. Godoy, Eric Monsalves, Alexandra Kilian, Boris Krischek, Aisha Ghare, Allan Vescan, Fred Gentili, and Gelareh Zadeh
While the use of endoscopic approaches has become increasingly accepted in the resection of pituitary adenomas, limited evidence exists regarding the success of this technique for patients with large and giant pituitary adenomas. This study reviews the outcomes of a large cohort of patients with large and giant pituitary adenomas who underwent endoscopic endonasal transsphenoidal surgery at the authors' institution and focuses on identifying factors that can predict extent of resection and hence aid in developing guidelines and indications for the use of endoscopic endonasal transsphenoidal surgery versus open craniotomy approaches to large and giant pituitary adenomas.
The authors reviewed 487 patients who underwent endoscopic endonasal transsphenoidal resection of sellar masses. From this group, 73 consecutive patients with large and giant pituitary adenomas (defined as maximum diameter ≥ 3 cm and tumor volume ≥ 10 cm3) who underwent endoscopic endonasal transsphenoidal surgery between January 1, 2006, and June 6, 2012, were included in the study. Clinical presentation, radiological studies, laboratory investigations, tumor pathology data, clinical outcomes, extent of resection measured by volumetric analysis, and complications were analyzed.
The mean preoperative tumor diameter in this series was 4.1 cm and the volume was 18 cm3. The average resection rate was 82.9%, corresponding with a mean residual volume of 3 cm3. Gross-total resection was achieved in 16 patients (24%), near-total in 11 (17%), subtotal in 24 (36%), and partial in 15 (23%). Seventy-three percent of patients experienced improvement in visual acuity, while 24% were unchanged. Visual fields were improved in 61.8% and unchanged in 5.5%. Overall, 27 patients (37%) experienced a total of 32 complications. The most common complications were sinusitis (14%) and CSF leak (10%). Six patients underwent subsequent radiation therapy because of aggressive tumor histopathology. No deaths occurred in this cohort of patients. Statistically significant predictors of extent of resection included highest Knosp grade (p = 0.001), preoperative tumor volume (p = 0.025), preoperative maximum tumor diameter (p = 0.002), hemorrhagic component (p = 0.027), posterior extension (p = 0.001), and sphenoid sinus invasion (p = 0.005).
Endoscopic endonasal transsphenoidal surgery is an effective treatment method for patients with large and giant pituitary adenomas, which results in high (> 80%) rates of resection and improvement in visual function. It is not associated with high rates of major complications and is safe when performed by experienced surgeons. The preoperative Knosp grade, tumor volume, tumor diameter, hemorrhagic components on MRI, posterior extension, and sphenoid sinus invasion may allow a prediction of extent of resection and in these patients a staged operation may be required to maximize extent of resection.
Joshua D. Burks, Katie L. Gant, James D. Guest, Aria G. Jamshidi, Efrem M. Cox, Kim D. Anderson, W. Dalton Dietrich, Mary Bartlett Bunge, Barth A. Green, Aisha Khan, Damien D. Pearse, Efrat Saraf-Lavi, and Allan D. Levi
In cell transplantation trials for spinal cord injury (SCI), quantifiable imaging criteria that serve as inclusion criteria are important in trial design. The authors’ institutional experience has demonstrated an overall high rate of screen failures. The authors examined the causes for trial exclusion in a phase I, open-lab clinical trial examining the role of autologous Schwann cell intramedullary transplantation. Specifically, they reviewed the imaging characteristics in people with chronic SCI that excluded applicants from the trial, as this was a common cause of screening failures in their study.
The authors reviewed MRI records from 152 people with chronic (> 1 year) SCI who volunteered for intralesional Schwann cell transplantation but were deemed ineligible by prospectively defined criteria. Rostral-caudal injury lesion length was measured along the long axis of the spinal cord in the sagittal plane on T2-weighted MRI. Other lesion characteristics, specifically those pertaining to lesion cavity structure resulting in trial exclusion, were recorded.
Imaging records from 152 potential participants with chronic SCI were reviewed, 42 with thoracic-level SCI and 110 with cervical-level SCI. Twenty-three individuals (55%) with thoracic SCI and 70 (64%) with cervical SCI were not enrolled in the trial based on imaging characteristics. For potential participants with thoracic injuries who did not meet the screening criteria for enrollment, the average rostral-caudal sagittal lesion length was 50 mm (SD 41 mm). In applicants with cervical injuries who did not meet the screening criteria for enrollment, the average sagittal lesion length was 34 mm (SD 21 mm).
While screening people with SCI for participation in a cell transplantation clinical trial, lesion length or volume can exclude potential subjects who appear appropriate candidates based on neurological eligibility criteria. In planning future cell-based therapy trials, the limitations incurred by lesion size should be considered early due to the screening burden and impact on candidate selection.
Aisha Khan, Anthony Diaz, Adriana E. Brooks, S. Shelby Burks, Gagani Athauda, Patrick Wood, Yee-Shuan Lee, Risset Silvera, Maxwell Donaldson, Yelena Pressman, Kim D. Anderson, Mary Bartlett Bunge, Damien D. Pearse, W. Dalton Dietrich, James D. Guest, and Allan D. Levi
Schwann cells (SCs) have been shown to play an essential role in axon regeneration in both peripheral nerve injuries (PNIs) and spinal cord injuries (SCIs). The transplantation of SCs as an adjunctive therapy is currently under investigation in human clinical trials due to their regenerative capacity. Therefore, a reliable method for procuring large quantities of SCs from peripheral nerves is necessary. This paper presents a well-developed, validated, and optimized manufacturing protocol for clinical-grade SCs that are compliant with Current Good Manufacturing Practices (CGMPs).
The authors evaluated the SC culture manufacturing data from 18 clinical trial participants who were recruited for autologous SC transplantation due to subacute SCI (n = 7), chronic SCI (n = 8), or PNIs (n = 3). To initiate autologous SC cultures, a mean nerve length of 11.8 ± 3.7 cm was harvested either from the sural nerve alone (n = 17) or with the sciatic nerve (n = 1). The nerves were digested with enzymes and SCs were isolated and further expanded in multiple passages to meet the dose requirements for transplantation.
An average yield of 87.2 ± 89.2 million cells at P2 and 150.9 ± 129.9 million cells at P3 with high viability and purity was produced. Cell counts and rates of expansion increased with each subsequent passage from P0 to P3, with the largest rate of expansion between P2 and P3. Larger harvest nerve lengths correlated significantly with greater yields at P0 and P1 (p < 0.05). In addition, a viability and purity above 90% was sustained throughout all passages in nearly all cell products.
This study presents reliable CGMP-compliant manufacturing methods for autologous SC products that are suitable for regenerative treatment of patients with SCI, PNI, or other conditions.