Neuromonitoring Signal Changes in Degenerative Cervical Myelopathy: An Analysis of Risk Factors for Signal Drops During Posterior Cervical Decompression.

OBJECTIVE: To analyze intraoperative neuromonitoring data of patients with degenerative cervical myelopathy undergoing cervical laminectomy and assess the incidence of signal drops and their risk factors. METHODS: This retrospective observational study included patients with degenerative cervical myelopathy who underwent cervical laminectomy with intraoperative neuromonitoring between July 2018 and March 2023. We analyzed the signal changes for any correlation with the type of pathology (ossified posterior longitudinal ligament vs. cervical spondylotic myelopathy [CSM]) and clinical (severity of myelopathy, duration of symptoms) and radiological (length of cord signal changes and K-line) parameters. RESULTS: Of 100 degenerative cervical myelopathy cases, 55 were diagnosed as OPLL and 45 as CSM. Signal drops were recorded in 26 patients-14 persistent drops and 12 transient drops. True positive drops were seen in 4 patients (2 OPLL and 2 CSM), 3 of whom had sustained bimodal drops (both somatosensory evoked potentials and motor evoked potentials). Signal drops were significantly more frequent with OPLL compared with CSM (P < 0.01). Ten of 14 persistent signal drops and 9 of 12 transient drops were seen in patients in OPLL. Continuous OPLL, negative K-line, hill type OPLL, severity of myelopathy, and longer duration of symptoms were risk factors for signal drops. CONCLUSIONS: Patients with cervical OPLL have a higher incidence of false positive and transient signal drops after decompression compared with patients with CSM. Longer duration of symptoms, high-grade myelopathy, continuous OPLL, hill type OPLL, and negative K-line were risk factors for signal drops.

Lumbar Disc Herniation and Preoperative Modic Changes: A Prospective Analysis of the Clinical Outcomes After Microdiscectomy.

STUDY DESIGN: Prospective comparative cohort study. OBJECTIVES: The study aims to elucidate the relationship between Modic endplate changes and clinical outcomes after a lumbar microdiscectomy. METHODS: Consecutive patients undergoing microdiscectomy for lumbar disc herniation (LDH) were prospectively studied. Pre-operative clinical and radiological parameters were recorded. The pain was assessed by Numeric pain rating scale (NPRS), and functional assessment by Oswestry Disability Index (ODI). Minimal clinically important difference (MCID) in outcome was calculated for both the groups. Complications related to surgery were studied. Follow-up was done at 6 weeks, 3 months, 6 months and 1 year. Mac Nab criteria were used to assess patient satisfaction at 1 year. RESULTS: Out of 309 patients, 86 had Modic changes, and 223 had no Modic changes. Both groups had similar back pain (p-value: 0.07) and functional scores (p-value: 0.85) pre-operatively. Postoperatively patients with Modic changes had poorer back pain and ODI scores in the third month, sixth month and 1 year (p-value: 0.001). However, MCID between the groups were not significant (p-value: 0.18 for back pain and 0.58 for ODI scores). Mac Nab criteria at 1 year were worse in Modic patients (p-value: 0.001). No difference was noted among Modic types in the pre-operative and postoperative pain and functional outcomes. Four patients in Modic group (4.7%) and one patient in the non-Modic group (0.5%) developed postoperative discitis (p-value: 0.009). CONCLUSIONS: Preoperative Modic changes in lumbar disc herniation is associated with less favorable back pain, functional scores and patient satisfaction in patients undergoing microdiscectomy.

Preemptive analgesia for postoperative pain relief in lumbosacral spine surgeries: a randomized controlled trial.

BACKGROUND CONTEXT: Administration of analgesic medication, before the actual onset of painful stimulus, is more effective than that after the onset of painful stimulus. This is the principle of preemptive analgesia. Although it is often considered superior to other forms of analgesia, its role in postoperative pain relief after lumbosacral spinal surgery has not been fully investigated. PURPOSE: To analyze the efficacy of preemptive analgesia with a single caudal epidural injection for patients undergoing surgeries on the lumbosacral spine by the posterior approach. STUDY DESIGN/SETTING: Randomized, double-blinded and controlled clinical trial. PATIENT SAMPLE: Eighty-two patients who underwent discectomy in the lumbosacral spine by the posterior approach, with or without instrumentation, were randomized to the control group (n=40) and to the study group (n=42). METHODS: Patients in control group received a single caudal epidural injection of 20 ml of normal saline. Patients in study group received a single caudal epidural injection of 20 ml containing bupivacaine and tramadol as the active agents. The time interval between this injection and the surgical incision was never less than 20 minutes in either of the groups. This facilitated enough time for the drug to get fixed to the nerve roots, leading to effective preemptive analgesia. OUTCOME MEASURES: Patients were monitored for postoperative pain immediately after surgery when they had completely recovered and regained consciousness from general anesthesia, and subsequently 4, 8, 12 and 24 hours thereafter. Pain was quantified using the visual analog scale (VAS) and the verbal rating scale (VRS). The time at which supplemental analgesic medication was first demanded in the postoperative period by the patient was also noted. RESULTS: The two groups were comparable for age, sex, body weight and the type of surgery they underwent. Because the data did not have a normal Gaussian distribution, the one-tailed Mann-Whitney test, being a nonparametric test, was adopted for statistical analysis. Accordingly, VAS and VRS values at all time intervals were significantly lower (p<.0001) in the study group as compared with the control group. This indicated significantly better pain relief in the study group. There was also a significant delay (p=.0041) in the first demand for supplemental analgesic medication in the postoperative period in the study group. No complication specific to the procedure was noted except for the development of postoperative urinary retention, which was transient and appropriately managed with urinary catheterization. CONCLUSIONS: Preemptive analgesia with a single caudal epidural injection of bupivacaine and tramadol is a safe, simple and effective method for postoperative pain relief.

Intra-operative computer navigation guided cervical pedicle screw insertion in thirty-three complex cervical spine deformities.

BACKGROUND: Cervical pedicle screw fixation is challenging due to the small osseous morphometrics and the close proximity of neurovascular elements. Computer navigation has been reported to improve the accuracy of pedicle screw placement. There are very few studies assessing its efficacy in the presence of deformity. Also cervical pedicle screw insertion in children has not been described before. We evaluated the safety and accuracy of Iso-C 3D-navigated pedicle screws in the deformed cervical spine. MATERIALS AND METHODS: Thirty-three patients including 15 children formed the study group. One hundred and forty-five cervical pedicle screws were inserted using Iso-C 3D-based computer navigation in patients undergoing cervical spine stabilization for craniovertebral junction anomalies, cervico-thoracic deformities and cervical instabilities due to trauma, post-surgery and degenerative disorders. The accuracy and containment of screw placement was assessed from postoperative computerized tomography scans. RESULTS: One hundred and thirty (89.7%) screws were well contained inside the pedicles. Nine (6.1%) Type A and six (4.2%) Type B pedicle breaches were observed. In 136 levels, the screws were inserted in the classical description of pedicle screw application and in nine deformed vertebra, the screws were inserted in a non-classical fashion, taking purchase of the best bone stock. None of them had a critical breach. No patient had any neurovascular complications. CONCLUSION: Iso-C navigation improves the safety and accuracy of pedicle screw insertion and is not only successful in achieving secure pedicle fixation but also in identifying the best available bone stock for three-column bone fixation in altered anatomy. The advantages conferred by cervical pedicle screws can be extended to the pediatric population also.