Upper cervical spine tuberculosis (TB) is a rare infectious disease, which accounts for only 0.3 to 1% of all cases of spinal TB [1,2,3]. The upper cervical spine is the most mobile and most complex part of the cervical spine. Because of the relatively wide spinal canal and strong tolerance to spinal cord compression in this section of the spine, the early clinical symptoms of upper cervical spine TB are relatively silent and tend to go unnoticed by patients. By the time the patient seeks treatment, extensive bone and soft-tissue destruction have usually occurred, resulting in spinal cord compression and upper cervical spine instability, which can seriously damage the medulla and spinal cord, and cause paralysis, bulbar paralysis, and respiratory dysfunction [4,5,6]. Therefore, the window of opportunity for conservative treatment is often missed, and the deep position of the infection and the severe damage to the atlantoaxial lateral mass, vertebral body, and pedicle usually necessitate surgical intervention [7].
Currently, transoral debridement combined with fixation via the posterior approach is used to clear the lesion and stabilize the upper cervical spine [8]. However, this procedure carries a certain risk of associated bacterial contamination through the oral cavity. Furthermore, prolonged intubation or tracheotomy, and postoperative enteral tube feeding are unavoidable [9]. It has been reported that debridement via the anterior cervical and retropharyngeal approach combined with posterior fixation and fusion can achieve desirable results [10]. However, it is difficult to operate under direct vision owing to the anatomical complexity of the upper cervical spine. An endoscopic approach may be used to resolve this problem.
This retrospective study aimed to determine the feasibility and efficacy of endoscopic anterior cervical debridement combined with posterior fixation and fusion for the treatment of patients with upper cervical spine TB.
Study design and ethics statement
This study was a retrospective review of the medical data of 17 patients with upper cervical spine TB who underwent endoscopy-assisted anterior cervical debridement with posterior fixation and fusion at our Hospital, between June 2008 and January 2016.
Patient selection criteria
The inclusion criteria for this study were as follows: (i) persistent neck pain and stiffness caused by cervical spinal instability, (ii) progressive spinal cord compression, (iii) unpreventable progressive atlantoaxial dislocation, and (iv) lack of lesion absorption despite anti-TB treatment. The exclusion criteria were as follows: (i) intolerance to surgery as determined by preoperative evaluations, (ii) effective conservative treatment, and (iii) patient’s inability to behave autonomously, rendering complete follow-up impossible.
Clinical evaluations and diagnosis
All patients reported having non-specific symptoms, such as neck pain and stiffness, local tenderness, moderate fever, sweats, weight loss, general weakness, and neurological dysfunction. No patient was HIV positive or had active pulmonary TB. In all patients, upper cervical spine TB was diagnosed on the basis of the clinical presentation, results of laboratory tests, and findings of imaging examinations, such as spinal radiography, computed tomography (CT), and magnetic resonance imaging (MRI). Neck pain was evaluated using the visual analogue scale (VAS), and neurological deficit was assessed using the American Spinal Injury Association (ASIA) impairment scale and the Japanese Orthopaedic Association (JOA) score.
Preoperative preparations
At least 2 weeks before the surgery, all patients received treatment with the following anti-TB drugs: 300 mg/day isoniazid, 450 mg/day rifampicin, 750 mg/day ethambutol, and 750 mg/day pyrazinamide. Nutrition support is essential, and was offered to all patients. Halo traction was used preoperatively to partially correct atlantoaxial subluxation. In addition, bed rest and regular neck collar protection were necessary. The operation was conducted only after anemia and hypoproteinemia had been effectively corrected, TB symptoms had been obviously relieved, and the erythrocyte sedimentation rate (ESR) had significantly declined.
Operative procedure
All patients underwent tracheal intubation under general anesthesia. Patients were placed in a prone position for the procedure, and halo traction was maintained throughout to stabilize the spinal column. A posterior midline incision was made from the occipital protuberance to the C4 spinous process to expose the occipital bone, posterior arch of the atlas, and the C2–C4 spinous processes and vertebral laminae. Lateral mass screws were inserted in the C2–C4 segments, according to the extent of the lesion. Two pre-bent titanium plate-rods or titanium rods were installed. Six holes were drilled into the occipital bone through the orifices along the sides of the titanium plate (to avoid piercing the inner plate), and skull screws were inserted. After stable fixation had been achieved, hemostasis and irrigation were performed repeatedly. The bone graft bed was roughened, and autologous iliac bone or allogeneic bone was grafted.
Afterwards, the halo traction was removed, and the patients were placed in a supine position with slight cervical extension. Next, a left- or right-sided anterior cervical transverse skin incision was made. The subcutaneous tissue and platysma were stripped in layers. The superficial fascia was bluntly dissected along the anterior border of the sternocleidomastoid muscle, which was in line with the skin incision. Sharp dissection was carried out along the deep platysma to reveal the deep fascia, which was longitudinally incised along the inner edge of the sternocleidomastoid. Next, the supraomohyoid was found and incised. The prevertebral space was entered via the interspace between the internal edge of the vascular sheath and the outer edge of the visceral sheath. The prevertebral loose tissue was sharply dissected. Then, the intervertebral space of C2–C3 was located with the C-arm X-ray machine.
Important anatomical structures were protected during the surgery. The carotid artery and sternocleidomastoid were mobilized laterally, and the esophagus, trachea, and suprahyoid muscles were retracted medially. The superior thyroid vessels and hypoglossal nerve were identified and adequately protected. Only then did the surgeon introduce the endoscope and manipulating instruments such as curette and burr. After the endoscope was inserted, the posterior pharyngeal wall was dissociated, and the anterior arch of C1, the vertebral body of C2, and intervertebral space of C2–C3 were revealed under endoscopy. The sequestrum, abscesses, and other lesions were debrided. The abscess cavity was repeatedly washed. The surgical cavity was filled with absorbable gelatin sponge for hemostasis, and 1.0 g streptomycin and 0.3 g isoniazid were locally administered in the surgical field. Finally, a drainage tube was inserted, and the wound was closed in layers. An intraoperative biopsy specimen was subjected to mycobacterial culture and histopathological examination, and typical caseating granulomas were observed in all patients.
For patients with nerve compression, anterior endoscopic debridement was performed first, and then posterior fixation and bone grafting were performed, to avoid further aggravation of the spinal cord compression caused by lesions when repositioning the patient. The surgical procedure was depicted in Fig. 1.
Postoperative care
When the drainage flow was < 30 mL/24 h, the drainage tube was removed. Intravenous antibiotics were used to prevent infection, and regular nutritional support was provided. After 5–7 days of bed rest, patients were allowed to ambulate while wearing a rigid cervical collar for effective neck support. The cervical collar was used for 3–6 months, and was removed when bone graft union was confirmed on X-ray examination. Depending on their general clinical condition, each patient was encouraged to undergo early physical rehabilitation to prevent thrombosis and improve nerve function. Standard anti-TB chemotherapy, as mentioned previously, was administered for 3 months, followed by 9–15 months of treatment with 450 mg/day rifampicin, 300 mg/day isoniazid, and 750 mg/day ethambutol.
Follow-up evaluations
The extent of postoperative decompression and graft and instrumentation placement as well as graft fusion status were routinely assessed using X-ray or CT examination. Blood routine examination, and liver- and kidney-function tests were regularly conducted during the anti-TB treatment to detect any adverse drug reactions. The following factors were recorded preoperatively, immediately postoperatively, and during follow-up: (i) ESR, (ii) VAS score for neck pain, (iii) functional outcomes as assessed using the Kirkaldy–Willis criteria [11] and (iv) neurological status as assessed using the ASIA grade and JOA score,
Statistical analysis
All statistical analyses were conducted using the SPSS version 24.0 statistical software package. The preoperative, postoperative, and follow-up clinical data were compared using the paired t test. Discrepancies in normal data distributions were analyzed using the rank sum test. P < 0.05 was considered to indicate statistically significant differences.
