A 64-year-old male patient presented at our pain clinic with severe cervical pain. His medical history indicated a neck injury during military service 20 years prior, followed by posterior foraminotomy at C5-7 and anterior cervical discectomy and fusion at C5-6 and C6-7. Despite these surgeries, he experienced persistent cervical and upper extremity radicular pain and was diagnosed with SCI, multiple surgery-related cervical radiculopathies, and chronic postspinal surgery cervical pain. He had a spinal cord stimulatorm (SCS) implanted at another hospital two years prior and reported some reduction in upper extremity radicular pain but no improvement in neck pain.

At the time of presentation, the patient was on an extensive medication regimen, including a fentanyl patch (37 μg), oxycodone (40 mg bid), tapentadol (100 mg bid), duloxetine (30 mg bid), gabapentin (300 mg tid), acetaminophen (1,300 mg tid), and tramadol (150 mg tid). Nevertheless, he reported persistent pain, with a numeric rating scale (NRS) score of 10.

Anteroposterior and lateral views of the cervical spine confirmed no evidence of stenosis due to bony spurs. SCS lead from the previous surgery was positioned at C3-5 (Fig. 1). Electromyographic nerve conduction velocity tests revealed findings consistent with right C6-T1 and left C7-T1 radiculopathy with mild partial axonotmesis. Bilateral hypothermia below the wrist was observed by digital infrared thermal imaging.

The patient’s pain persisted even after SCS, necessitating additional treatment. He received cervical epidural and facet joint blocks, which provided minimal relief. A cervical medial branch block offered temporary pain relief for 1-2 days, prompting radiofrequency ablation of the cervical medial branch. However, the effects of this procedure lasted for only 1-2 weeks.

After patient consent was obtained, an intrathecal morphine infusion trial was performed. We calculated the oral MED to be 333.8 mg/day, considering the current intake of narcotic analgesics. Accordingly, we administered an intrathecal injection of morphine (0.4 mg in 4 ml normal saline [N/S]) at the L3/4 level. After the procedure, the patient’s pain decreased to 3-5 points on the NRS.

At the next visit, the patient received another intrathecal injection of morphine (0.5 mg) in 4 ml of N/S at the L3/4 level, which provided better pain relief. No adverse effects, such as urinary retention or pruritus, were observed after the intrathecal morphine injections.

Subsequently, the patient was admitted to our hospital for ITDD placement. The patient was positioned prone with a pad under the abdomen to maintain slight lumbar flexion. A skin incision was made approximately 4 cm from the needle tip, parallel to the spinous process at the L3-4 level, approximately 1-1.5 vertebral bodies below the final target point. A Tuohy needle was inserted under fluoroscopic guidance via the paramedian approach. The stylet was removed to verify the needle placement in the spinal space by ensuring CSF flow. The intrathecal catheter was inserted through the Tuohy needle, and its tip was maneuvered to reach the C6 level (Fig. 2).

The guidewire and Tuohy needle of the intrathecal catheter were carefully removed, and the tip of the catheter was stabilized with forceps to prevent CSF leakage during tunneling. The patient was then placed in the right lateral decubitus position, and a 5 cm horizontal incision was made in the left lower abdomen to create a subcutaneous pocket. The spinal and abdominal incisions were connected subcutaneously using a catheter passer. After the proper connection of the intrathecal catheter was ensured, the flow of the CSF was rechecked, and the catheter was connected to the pump. The pump was then placed in the subcutaneous pocket, with the intrathecal catheter securely tucked into the back of the pump (Fig. 3). The skin was sutured and dressed.

The drug delivery reservoir was filled with 100 mg (10 ml) of morphine sulfate mixed with 10 ml of N/S, resulting in a total volume of 20 ml. The morphine infusion rate was adjusted to 0.5 mg/day.

One day postoperatively, the patient’s pain level decreased to an NRS score of approximately 3, with no major adverse events such as pruritus, urinary retention, nausea, vomiting, or constipation. The patient’s fentanyl patch dosage was reduced from 37 μg/h to 12 μg/h, oxycodone from 40 mg bid to 20 mg bid, and tapentadol was discontinued owing to effective pain control. The oral MED was reduced from 333.8 mg/day to 133.8 mg/day.

After the surgical wound healed, the patient was discharged and monitored for regular morphine sulfate refills into the drug delivery reservoir every 6 months.

In this case, a patient with a cervical SCI experienced persistent pain even after surgery and excessive opioid use, with an NRS score of 8 or higher. Despite the implantation of a SCS, the pain remained uncontrolled. The pain was managed with continuous morphine infusion via an intrathecal catheter placed in the cervical spine. Although the placement of an intrathecal catheter in the cervical spine is challenging, this method can be an effective option for pain control if SCS fails.

Intrathecal drug delivery involves the direct administration of drugs into the CSF around the spinal cord. This technique bypasses the blood-brain barrier, enabling targeted delivery to the central nervous system and reducing systemic side effects [8].

A primary benefit of intrathecal drug delivery in cervical SCI is its ability to provide localized pain relief. Intrathecal drug delivery systems can effectively target the mechanisms underlying pain by delivering analgesics directly to the spinal cord, thereby providing significant relief. In addition, these systems offer precise control over drug dosing and timing, allowing for individualized treatment regimens tailored to the patient’s specific needs. This level of customization is crucial for managing pain and improving the quality of life of patients with cervical SCI [9].

Placing a catheter in the thoracic or lumbar region is relatively easy. However, advancing the catheter from the lumbar to the cervical region, as in this case, is more challenging. Prior to our case, a case of ITDD with morphine using an intrathecal catheter at the C1 level was reported in a patient with refractory oropharyngeal cancer pain [10].

The spread of drugs within the CSF is limited, and drugs are unevenly distributed within the spinal canal. Therefore, ITDD is most effective near the catheter tip. The tip of the catheter is typically placed near the site of the most severe pain based on the clinical judgment of the pain management physician [6,11].

In our case, the patient experienced neck and radicular pain in the C5-7 region because of a cervical SCI. We determined that access to the cervical spine would be difficult as the patient underwent foraminotomy at C5-7, anterior fusion at C5-6 and C6-7, with the SCS lead accessing the epidural space at the C7/T1 level and placed at the C3-5 level. In addition, insertion of an intrathecal catheter after an intrathecal puncture in the cervical spine is too risky for nerve damage, and the drug is localized around the catheter. Therefore, an intrathecal catheter was inserted in the lumbar spine at the L3/4 level to allow the catheter tip to reach the C6 level. Optimal placement near the site of pain can be challenging in patients with neck pain because of concerns regarding the side effects of intrathecal medications near critical brainstem structures. However, in other rare case reports and our case, no side effects attributable to drug spread to the brainstem were observed. Nonetheless, the use of intrathecal drug delivery systems for cervical SCI requires careful patient selection and comprehensive multidisciplinary care [11].

Patients with postsurgical SCI who have long-term spinal conditions often have difficulty maintaining certain postures, and the procedure itself is often difficult. Given these difficulties, the patient was positioned under general anesthesia. The intrathecal catheter was then placed in the lateral position, starting at the lumbar spine and working up to the cervical spine. The patient’s history of two previous operations on the cervical spine and the SCS lead in the cervical spine made determining the position of the catheter tip challenging; however, general anesthesia allowed us to take time and place the catheter tip in the desired position. General anesthesia ensures that the patient is unconscious and pain-free, allowing the surgical team to concentrate solely on the technical aspects of catheter placement. This is particularly beneficial for procedures involving complex spinal anatomy or for patients who cannot tolerate local anesthesia [12].

Before device implantation, patients underwent a comprehensive evaluation. This process helps determine their suitability for intrathecal therapy and identify any potential contraindications. The procedure involves the surgical implantation of a pump and catheter, which carries risks such as infection, spinal fluid leakage, and potential catheter migration. Regular monitoring and maintenance of the pump and catheter are required to ensure proper functioning and prevent complications. Not all patients are suitable candidates for ITDD, and careful preoperative assessment is required to evaluate the potential benefits and risks. Therefore, careful assessment is essential to ensure the safety and efficacy of the treatment [13,14].

In conclusion, this case report suggests that the ITDD system is a valuable treatment option for patients with cervical SCIs who do not respond to conventional treatments or SCS. These systems can effectively manage pain and enhance functional outcomes by delivering medication directly to the site of injury. Further research and clinical experience are necessary to optimize patient selection criteria and refine treatment protocols to maximize benefits.