Faculty Bibliography

INTRODUCTION/BACKGROUND:Spinal cord stimulation (SCS) can provide long-term pain relief for various chronic pain conditions, but some patients have no relief with trial stimulation or lose efficacy over time. To "salvage" relief in patients who do not respond or have lost efficacy, alternative stimulation paradigms or anatomical targets can be considered. Dorsal root ganglion stimulation (DRG-S) has a different mechanism of action and anatomical target than SCS. OBJECTIVES/OBJECTIVE:We assessed DRG-S salvage therapy outcomes in patients who did not respond to SCS or had lost SCS efficacy. MATERIALS AND METHODS/METHODS:We retrospectively included consecutive patients from 2016 to 2020 who were salvaged with DRG-S after failed SCS trials (<50% pain reduction) or who had lost efficacy after permanent SCS. We compared numerical rating scale (NRS) pain, Oswestry disability index (ODI), health-related quality of life (EuroQol five-dimensions five-level), and oral morphine equivalent (OME) opioid requirements before DRG-S salvage and at patients' last follow-up. RESULTS:A total of 60 patients who had failed SCS were salvaged with DRG-S. The mean age was 56 ± 12 years, and the most common diagnoses were complex regional pain syndrome (n = 24) and failed back surgery syndrome (n = 24). The most common failed modalities included tonic (n = 32), Burst (n = 18), and high-frequency (n = 10) SCS. The median follow-up duration of salvage DRG-S was 34 months. With DRG-S, NRS decreased (8.7 ± 1.2 to 3.8 ± 2.1), and OME declined (median 23 mg to median 15 mg), whereas EuroQol 5D scores increased (0.40 ± 0.15 to 0.71 ± 0.15), and ODI improved (64 ± 14% to 31 ± 18%) (all p < 0.05). CONCLUSIONS:DRG-S can be used in patients with chronic pain who have previously failed to receive persistent benefit from SCS.

INTRODUCTION/BACKGROUND:Dorsal root ganglion stimulation (DRG-S), has demonstrated superiority in the treatment of complex regional pain syndrome and causalgia. Lead migration and fracture impact DRG-S therapeutic stability. Lead anchoring reduces DRG-S lead migration without increasing lead fracture. Lead fracture may be related to lead entrapment in the superficial fascial plane. A novel medialized approach for lead placement and anchoring is presented to address these issues. METHODS:We suggest an alternative technique for implanting percutaneous DRG-S leads at the T10-L5 levels. RESULTS:A novel medialized ipsilateral technique for lead placement and anchoring for single, bilateral, and adjacent segment placement is presented. The Tuohy needle puncture site is medial to the pedicle and adjacent to the spinous process, two vertebral levels caudad to the target foramen. Trajectory is maintained in the sagittal plane, to access the caudad interlaminar space near the midline. This technique allows for ipsilateral or contralateral lead placement. After epidural access, the introducer sheath is rotated toward the targeted foramen and advanced. The guidewire followed by the lead is passed, and once lead position is confirmed, tension 'S' loops are created, followed by anchoring to the deep fascia. CONCLUSION/CONCLUSIONS:We describe a new paramedian technique for DRG-S lead placement. We propose it will decrease DRG-S complication rates through anchoring to reduce migration and by avoiding the fascial planes thought to be responsible for fracture. Long-term outcomes applying our proposed techniques are required for determining the true impact, however, early anecdotal results suggest that these new techniques are favorable.

STUDY DESIGN/METHODS:This study is a single-center retrospective radiographic review. OBJECTIVES/OBJECTIVE:The objective of this study is to evaluate a novel measurement parameter, mandibular slope (MS), as a measure of horizontal gaze. INTRODUCTION/BACKGROUND:Assessment of sagittal spinal alignment is essential in the evaluation of spinal deformity patients. Ability to achieve a horizontal gaze, a parameter of sagittal alignment, is needed for the performance of daily activities. Standard measures of horizontal gaze, including the gold-standard chin-brow to vertical angle (CBVA) and the surrogate measures McGregor's line (McGS) and Chamberlain's line (CS), require high-quality imaging, precise head positioning, and reliance on difficult to view visual landmarks. A novel measurement parameter, MS, utilizing the caudal margin of the mandible on standard lateral spine radiographs is proposed. METHODS:90 radiographs from spine deformity patients with or without spinal implants from a single center were evaluated. Three spine surgery fellows independently measured CBVA, McGS, CS, and MS at two timepoints at least one week apart to assess accuracy and reliability. MS was measured as the angle created by the inferior edge of the mandibular body and the horizontal. Formulas for calculating CBVA based on the above parameters were derived and compared to the actual CBVA. RESULTS:Mean age was 49.7 years, 76 females and 14 males. CBVA correlated with CS, McGS, and MS, r = 0.85, 0.81, and 0.80, respectively (p < 0.001). Standard error between real CBVA and calculated CBVA using CS (0.4 ± 4.79) and McGS (0.4 ± 3.9) was higher than that calculated using MS (- 0.2 ± 4.3). ICC demonstrated the highest inter-observer reliability with MS (0.999). MS had the highest intra-observer reliabilities 0.975, 0.981, and 0.988 (p < 0.001); CS and McGS also demonstrated high intra-observer reliability. CONCLUSIONS:MS is a promising measure of horizontal gaze that correlates highly with CBVA, has excellent intra- and inter-observer reliability with CBVA, and is easily measured using standard lateral spine radiographs.

OBJECTIVES/OBJECTIVE:Intrathecal drug delivery systems (IDDS) are an important method of pain control for patients with refractory oncologic pain. Local anesthetics such as bupivacaine have been infused either alone or with opioids. While effective, bupivacaine can cause adverse effects such as numbness, weakness, and urinary retention. This study looks to establish a safe and efficacious fixed bupivacaine dosing algorithm in intrathecal pumps for cancer patients. MATERIALS AND METHODS/METHODS:A bupivacaine dosing algorithm was developed using data from 120 previous patients who underwent IDDS placement at Memorial Sloan Kettering Cancer Center. The outcomes were then evaluated for 43 subsequent patients who were treated with bupivacaine IDDS according to our aforementioned algorithm. RESULTS:Our data show that in patients treated with our bupivacaine guideline, visual analog pain scale scores decreased by 59% and oral morphine equivalence decreased by 70% from the period between IDDS implantation until discharge from the MSKCC hospital. However, 16.3% of our patients had bupivacaine-related side effects. CONCLUSIONS:For oncological patients, our data and experience support the initiation of intrathecal bupivacaine at the following doses: 5 mg/day for catheter tips in the cervical spine, 8 mg/day for catheter tips at T1-4, and 10 mg/day for catheter tips at T5-8. Given the higher likelihood of adverse effects in catheters at T9-12 and the lumbar spine, we start at 8 mg/day with close follow-up of the patient. Initiating these doses allow our patients to safely reach adequate analgesia faster, with a shorter hospitalization and quicker return to anti-cancer therapy.

OBJECTIVE:The sympathetic nervous system has a recognized role in transmission of pain, and the lumbar sympathetic blockade is intended to provide analgesia. We share our experiences of lumbar sympathetic blockade in the treatment of cancer-related pain. METHODS:We performed a retrospective analysis of patients with cancer-related pain in the back, abdomen, pelvis, or legs treated at Memorial Sloan Kettering Cancer Center between 2000 and 2018 undergoing lumbar sympathetic blockade at L2 or L3. Blocks were accomplished by injection of local anesthetic or local anesthetic with steroid under fluoroscopy. We measured numerical rating scale scores, percent relief, and relief time. The primary end point was defined as "effective" or "ineffective" pain relief. Effective pain relief was defined as ≥30% relief for at least one day. RESULTS:We identified 124 data points of lumbar sympathetic blockade at L2 or L3, of which 57 were with complete data and used for analysis. Peri-injection, 42 data points had active disease whereas 15 were in remission. Lumbar sympathetic blockade was 67% effective in the back pain cohort, 82% effective in the abdominopelvic pain cohort, and 75% effective in the leg pain cohort. Seventeen data points went on to neurolysis, two to neuromodulation, and eight to intrathecal pump implantation. CONCLUSIONS:Lumbar sympathetic blockade is effective for back, abdominopelvic, and leg pain related to cancer and its treatments. Future research should be aimed at refining its role within multimodal pain management.

OBJECTIVE:Neck and back pain are highly prevalent conditions that account for major disability. The Neck Disability Index (NDI) and Oswestry Disability Index (ODI) are the two most common functional status measures for neck and back pain. However, no single instrument exists to evaluate patients with concurrent neck and back pain. The recently developed Total Disability Index (TDI) combines overlapping elements from the ODI and NDI with the unique items from each. This study aimed to prospectively validate the TDI in patients with spinal deformity, back pain, and/or neck pain. METHODS:This study is a retrospective review of prospectively collected data from a single center. The 14-item TDI, derived from ODI and NDI domains, was administered to consecutive patients presenting to a spine practice. Patients were assessed using the ODI, NDI, and EQ-5D. Validation of internal consistency, test-retest reproducibility, and validity of reconstructed NDI and ODI scores derived from TDI were assessed. RESULTS:A total of 252 patients (mean age 55 years, 56% female) completed initial assessments (back pain, n = 115; neck pain, n = 52; back and neck pain, n = 55; spinal deformity, n = 55; and no pain/deformity, n = 29). Of these patients, 155 completed retests within 14 days. Patients represented a wide range of disability (mean ODI score: 36.3 ± 21.6; NDI score: 30.8 ± 21.8; and TDI score: 34.1 ± 20.0). TDI demonstrated excellent internal consistency (Cronbach's alpha = 0.922) and test-retest reliability (intraclass correlation coefficient = 0.96). Differences between actual and reconstructed scores were not clinically significant. Subanalyses demonstrated TDI's ability to quantify the degree of disability due to back or neck pain in patients complaining of pain in both regions. CONCLUSIONS:The TDI is a valid and reliable disability measure in patients with back and/or neck pain and can capture each spine region's contribution to total disability. The TDI could be a valuable method for total spine assessment in a clinical setting, and its completion is less time consuming than that for both the ODI and NDI.

STUDY DESIGN: Retrospective review OBJECTIVE.: To evaluate preoperative variability in radiographic sagittal parameters in adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: In ASD surgical planning, deformity magnitude is determined from pre-op radiographs. The are no studies evaluating the clinical relevance and timing to repeat radiographs during interval clinic visits and timing to repeat radiograph for preoperative planning. METHODS: 139 ASD patients with minimum two pre-operative full body spine x-rays were included. Cervical, thoracic, lumbar, pelvic, and hip/knee sagittal alignment parameters were analyzed using dedicated spine measurement software. Patients were grouped by time intervals between x-rays: A: /=21 weeks. Changes in sagittal parameters were correlated to age and deformity magnitude (T1 pelvic angle [TPA] or pelvic tilt [PT] >20 degrees ). RESULTS: The cohort had mean age 59 years, mean BMI 27, 30% males, 95 patients with no prior spine surgery and 44 patients at minimum nine months since prior spine surgery. There were 25 patients in Group A, 38 in B, and 71 in C. All radiographic measures showed good time-based consistency at intervals <21 weeks (Groups A and B). Group C had significant increases in PT (1.5 degrees ) and hip extension (2.1 degrees ) (p < 0.05). These changes were greater in Group C patients with previous surgery (PT 3.7 degrees ; p < .006, hip extension 3.2 degrees ; p < .025). Greater interval changes in parameters were also associated with higher magnitude of deformity and younger patient age. CONCLUSIONS: All sagittal radiographic parameters were statistically consistent at intervals < 21 weeks. In patients with >21 weeks between interval x-rays, change in PT was greater than the standard error of measurement for patients with prior surgery or severe deformity. Consideration should be made to obtain new x-rays for adult spinal deformity patients when the interval between clinical visits exceeds 5 months. LEVEL OF EVIDENCE: 4.

STUDY DESIGN: Retrospective cohortObjective. To investigate the cervical alignment necessary for the maintenance of horizontal gaze depends on underlying thoracolumbar alignment SUMMARY OF BACKGROUND DATA.: Cervical curvature (CC) is affected by thoracic and global alignment. Recent studies suggest large variability in normative CC ranging from lordotic to kyphotic alignment. No previous studies have assessed the effect of global spinal alignment on CC in maintenance of horizontal gaze. METHODS: Patients without previous history of spinal surgery and were able to maintain their horizontal gaze while undergoing full body imaging were included. Patients were stratified based on thoracic kyphosis (TK) into (<30, 30-40, 40-50 and >50) then by SRS-Schwab sagittal vertical axis (SVA) modifier into (posterior alignment SVA<0, aligned 0-50 and malaligned >50 mm). Cervical alignment was assessed among SVA grade in TK groups. Stepwise linear regression analysis was applied on random selection of 60% of the population. A simplified formula was developed and validated on the remaining 40%. RESULTS: In each TK group (n = 118, 137, 125, 197), lower cervical curvature (C2-C7) was significantly more lordotic by increased Schwab SVA grade. T1 slope and cervical SVA significantly increased with increased thoracolumbar (C7-S1) SVA. Upper cervical curvature (C0-C2) and mismatch between T1 slope and cervical curvature (T1-CL) were similar. Regression analysis revealed LL minus TK (LL-TK) as an independent predictor (r = 0.640, r2 = 0.410) with formula: CC = 10 - (LL-TK)/2. Validation revealed that the absolute difference between the predicted CC and the actual CC was 8.5 degrees . Moreover, 64.2% of patients had their predicted C2-C7 values were within 10 degrees of the actual CC. CONCLUSIONS: Cervical kyphosis may represent normal alignment in a significant number of patients. However, in patients with SVA >50 and greater thoracic curvatures, cervical lordosis is needed to maintain the gaze. Cervical alignment can be predicted from underlying TK and lumbar lordosis, which may be clinically relevant when considering correction for thoracolumbar or cervical deformityLevel of Evidence: 3.