Faculty Bibliography

Lumbar stenosis is a very common degenerative spine condition that can result in radicular and claudication symptoms. Here we describe our experience with a novel midline interspinous process endoscopic decompression procedure that can be performed in awake patients as an outpatient procedure. An interspinous endoscopic lumbar laminectomy and bilateral foraminotomy technique is presented here. A step-by-step technique for accessing the lumbar central canal and bilateral foramina from a midline interspinous approach is presented. A Jamshidi needle, reamers, and side shaving manual drill are used to create an access channel for a 11.5 mm outer diameter tubular retractor. The Joimax rigid laminoscope with a 10 mm diameter and 6 mm working channel was then used to visualize the decompression procedure. The unique technical steps presented here make it possible to safely insert a 11.5 mm outer diameter tubular retractor for a "large" working channel endoscope. The procedure is so minimally invasive, it can be performed with the patient awake.

BACKGROUND:Cervical spine metastases with circumferential spinal cord compression often are treated with combined anteroposterior decompression and stabilization. In patients with large anterior neck masses, previous radiotherapy to the neck, or previous anterior neck surgery, however, anterior approaches may pose additional risk. In such cases, posterior-only approaches that allow for circumferential decompression and anterior column reconstruction may be beneficial. CASE DESCRIPTION/METHODS:We present the case of a 70-year-old man with follicular thyroid carcinoma metastatic to the cervical spine causing spinal cord compression. We used a posterior-only approach for a C6-C7 partial corpectomy and posterior decompression and fusion from C2 to T2. Our technique involved preoperative embolization of the right vertebral artery to safely gain access to the ventral surface of the spinal cord and vertebral bodies. Anterior column support was provided by a chest tube/polymethylmethacrylate construct, allowing the implant to be placed within the anterior column from a posterior approach without nerve root sacrifice. The patient tolerated the procedure well. He had no postoperative neurologic deficits. Two months later, he underwent a total thyroidectomy followed by stereotactic radiotherapy to the tumor bed (2700 cGy total, 3 fractions). At 1-year follow-up, he was active and without significant pain or focal neurologic deficits. CONCLUSIONS:We propose a novel approach to ventral/circumferential cervical spine tumors that combines epidural decompression and cervical stabilization via a posterior-only approach. By using a chest tube/polymethylmethacrylate construct, anterior column support can be achieved through a posterior approach without nerve root sacrifice.

BACKGROUND:Minimally invasive surgery using a mini-open lateral retropleural or retroperitoneal approach for corpectomy is a well-described procedure for treating unstable thoracolumbar burst fractures. Most surgeons have incorporated fluoroscopy for localization and determination of hardware placement accuracy; however, the utility of computer-assisted image-guided spinal navigation has not been well described. We report a series of mini-open lateral approach thoracolumbar corpectomy cases using either fluoroscopy or intraoperative computed tomography (iCT) with computer-assisted navigation and discuss the technical nuances and advantages of using iCT with navigation versus fluoroscopy. METHODS:A retrospective review and analysis was performed of the cases of 20 patients with thoracolumbar burst fractures surgically managed via mini-open lateral corpectomy with fluoroscopy (2013-2015) or iCT navigation (2015-2017). The surgical outcomes were evaluated by the estimated blood loss, operative time, hospital stay, and need for revision. The clinical outcomes were evaluated using the numerical rating scale pain score. Radiographic outcomes were assessed with follow-up CT scans. The results were statistically analyzed using the Wilcoxon-Mann-Whitney test. RESULTS:The mean follow-up period was 13.4 months for the fluoroscopy group and 14.7 months for the iCT group. No surgical complications developed and no revisions were required. No statistically significant differences were found between the groups in surgical or clinical outcomes. However, the radiation exposure to the surgeons was significantly less with the iCT group (P < 0.003). CONCLUSIONS:The use of iCT with spinal navigation for mini-open lateral corpectomy for thoracolumbar burst fractures yields perioperative and clinical outcomes comparable to those using traditional fluoroscopy, with decreased radiation exposure to surgeons.

BACKGROUND:Patients with far lateral disc herniation (FLDH) experience more severe pain and sensory symptoms compared with those with paracentral disc herniation. In addition, surgical intervention has both been more challenging and resulted in poorer outcomes. METHODS:We report our experience with intraoperative computed tomography (iCT) navigation-assisted minimally invasive tubular microdiscectomy via a paramedian approach with electrophysiological monitoring for precise 3-dimensional anatomical localization and early electrophysiological identification of the exiting nerve. RESULTS:Five patients presenting with weakness and pain refractory to conservative management underwent iCT navigation surgery for lumbar FLDH with electrophysiological monitoring. The mean decrease in the visual analog scale pain score was -7.1 and the modified MacNab criteria outcomes were good in 1 patient and excellent in 4 patients. CONCLUSIONS:These results from a small group of patients suggest this is a safe approach with the potential for improved outcomes in the surgical treatment of FLDH.

INTRODUCTION:The primary treatment for patients with sacral chordoma is en bloc surgical resection with negative margins, which has been shown to reduce local recurrence and tumor-related morbidity. Here we describe the use of intraoperative neuronavigation using preoperative spine magnetic resonance imaging fused to intraoperative computed tomography (CT) to create 3-dimensional tumor reconstructions in the operating room for intraoperative identification of bone and soft-tissue margins for maximal safe tumor resection. METHODS:A single-institution retrospective chart review was completed to encompass our experience of 6 consecutive patients who had sacral chordoma resections using our described navigation protocol. We collected data on patient demographics, previous surgeries, radiation therapy, preoperative examination, spinal levels involved, dural involvement, estimated blood loss, surgery time, tissue diagnosis, follow-up, postoperative examination, complications, and recurrence. Primary outcome was en bloc resection with negative margins as planned preoperatively. RESULTS:Negative surgical margins were achieved in 5 of 5 patients, who were preoperatively planned for en bloc resection with negative margins. The most common levels involved were S4-S5. All patients had a stable or improved neurologic examination after en bloc surgical resection. The average follow-up was 5.4 months ± 84.6 days. No patient had residual or recurrent tumor at last follow-up. CONCLUSIONS:Magnetic resonance imaging-CT fusion and 3-dimensional reconstruction techniques using an intraoperative CT scanner with image-guided navigation to aid preoperative planning and surgical resection of sacral chordomas are not well represented in the literature. This technique can be used for planning en bloc surgical resections and for more precisely identifying tumor margins intraoperatively.

BACKGROUND:Foot drop that results from compression of the exiting L5 nerve as a result of far lateral disc herniation (FLDH) at L5-S1 poses a significant surgical challenge to the minimally-invasive spine surgeon given the narrow corridor for an extraforaminal approach because of the high iliac crest. OBJECTIVES:Here we describe our experience with transforaminal endoscopic decompression for the treatment of foot drop secondary to FLDH at L5-S1. STUDY DESIGN:Retrospective case review. SETTING:This study took place in a single-center, academic hospital. METHODS:A technique for the transforaminal endoscopic treatment of foot drop secondary to L5-S1 FLDH is presented in a series of 5 consecutive patients treated over a period of 3 years. Preoperative and postoperative clinical data with 1-year follow-up are presented. RESULTS:A consecutive series of 211 patients who underwent transforaminal endoscopic treatment for lumbar radiculopathy between 2011 and 2014 are presented. Seventy-seven patients had L5-S1 discectomies and 5 of those patients presented with foot drop and FLDH. The mean visual analog scale score for radicular pain improved from an average pain score before surgery of 7.2 to 0.8 one year after surgery, and the mean motor score for anterior tibialis strength improved from an average motor score before surgery of 2.6 to 4.8 one year after surgery. LIMITATIONS:Small case series evaluated retrospectively with one year follow-up. CONCLUSIONS:Transforaminal endoscopic surgical access to FLDH pathology may be a unique approach to the treatment of foot drop because it allows for neural decompression of disc and foraminal pathology without requiring significant destabilizing bone removal. KEY WORDS:Endoscopic spine surgery, minimally-invasive, transforaminal, foot drop, far lateral disc herniation.

BACKGROUND:The sacroiliac joint complex (SIJC) is considered a major sources of chronic low back pain. Interventional procedures for sacroiliac (SI) joint pain tend to be short-lived and surgical treatment usually involves a fusion procedure. OBJECTIVES:To determine the clinical efficacy of endoscopically visualized radiofrequency treatment of the SIJC in the treatment of low back pain. STUDY DESIGN:Retrospective chart review. SETTING:This study took place in a single-center, orthopedic specialty hospital. METHODS:Patients received general anesthesia and under endoscopic visualization, radiofrequency ablation was performed on 1) the perforating branches that innervate the posterior capsule of the SI joint capsule, 2) along the course of the long posterior SI ligament, 3) the lateral edges of the S1, S2, and S3 foramen, and 4) the L4, L5, and S1 medial marginal nerve branches along the lateral facet margins. RESULTS:From January 2015 to June 2016, a total of 30 patients who met the precise inclusion criteria were treated with the endoscopic SIJC radiofrequency treatment for low back pain. The average patient was aged 56 years (19 women and 11 men), the average preoperative visual analog scale (VAS) score was 7.23, and the average Oswestry disability index (ODI) score was 44.8. VAS and ODI were measured at 3, 6, 9, 12, 15, 21 and 24 months: VAS was reduced from 7.23 at baseline to 2.82 at 24 months (61% reduction), and ODI was improved from 44.8 at baseline to 22.2 at 24 months (50% reduction). LIMITATIONS:Small retrospective case series. CONCLUSIONS:Full-endoscopic radiofrequency ablation of the large sensory SI joint innervation complex, that includes the sensory nerve branches along the lateral S1-3 foramina and the L4-S1 medial branches, is perhaps a minimally invasive surgical procedure that could provide significant relief of lumbar back pain in the carefully selected patient. KEY WORDS:Endoscopic spine surgery, minimally invasive, low back pain, sacroiliac joint, radiofrequency treatment.

OBJECTIVE:Perineural cysts are a benign spine pathology but, when they become symptomatic and require surgical treatment, represent a significant challenge to the spine surgeon. Here we describe our experience with a novel endoscopic approach to the biopsy, drainage, resection of the cyst wall, and direct cyst fenestration to the subarachnoid space. METHODS:A transforaminal endoscopic approach to a large lumbar 2-3 perineural cyst is presented here in a 25-year-old patient. A step-by-step technique for the biopsy, drainage, and resection of the cyst wall is presented. RESULTS:The patient underwent cyst resection and fenestration into the subarachnoid space without complication, with immediate relief of his preoperative symptoms and after 1 year remains symptom-free. CONCLUSIONS:Surgical treatment of perineural cysts in the spine represent a significant challenge to the surgeon, principally due to the risk of spinal fluid leak in the postoperative period. Transforaminal endoscopic surgical access to this disease pathology is a novel minimally invasive surgical approach presented here that allows diagnosis and treatment of a perineural cyst and can be performed in an awake patient.

BACKGROUND:Intramedullary spinal cord cavernous malformations (ISCCMs) are a rare entity. Most commonly, ISCCMs present with neurologic decline from lesion hemorrhage, which can be catastrophic and irreversible irrespective of surgical intervention. Given the challenging anatomic location of these lesions in highly critical neurologic areas, precise surgical localization and visualization is necessary to limit collateral damage during resection particularly for deep ISCCMs that do not present to a pial surface. CASE DESCRIPTION/METHODS:We present a case of a 54-year-old man who presented with incomplete paraplegia after hemorrhage of a deep ISCCM at T11. Surgical resection was undertaken using intraoperative computed tomography (CT) navigation assistance autofused with high-resolution preoperative magnetic resonance imaging for precise intramedullary lesion targeting and localization for myelotomy. Complete resection was demonstrated on postoperative imaging. At a 6-week follow-up appointment, the patient endorsed return of his bladder function and was noted to have some return of motor function to his left foot with 3 of 5 dorsiflexion. At 4 months, he had improved to 3 of 5 proximal, 4 of 5 distal on the left and 2 of 5 proximal, and 3 of 5 distal on the right. CONCLUSIONS:The approach represents a novel application of intraoperative CT navigation assistance in the resection of deep ISCCMs.

Post-operative CSF leaks are a known complication of spine surgery in general, and patients undergoing surgical intervention for spinal tumors may be particularly predisposed due to the presence of intradural tumor and a number of other factors. Post-operative CSF leaks increase morbidity, lengthen hospital stays, prolong immobilization and subject patients to a number of associated complications. Intraoperative identification of unintended durotomies and effective primary repair of dural defects is an important first step in the prevention of post-operative CSF leaks, but in patients who develop post-operative pseudomeningoceles, durocutaneous fistulae or other CSF-leak-related sequelae, early recognition and secondary intervention are paramount to preventing further CSF-leak-related complications and achieving the best patient outcomes possible. In this article, the incidence, risk factors and complications of CSF leaks after spine tumor surgery are reviewed, with an emphasis on avoidance of post-operative CSF leaks, early post-operative identification and effective secondary intervention.