Spinal surgery has evolved significantly over recent decades, with increasing volumes of procedures performed for trauma, degenerative conditions, infections, deformities, and neoplasms in low- and middle-income countries (LMICs) including Nigeria [1][2]. While surgical techniques and perioperative care have advanced, complications remain a significant concern, affecting patient outcomes, length of hospital stay, healthcare costs, and quality of life [3][4].

The epidemiology of spinal neurosurgery in Nigeria has been characterised by a systematic review and pooled analysis of 45,763 patients, which identified trauma and degenerative disease as the predominant indications, with a male-to-female ratio of approximately 2.5:1 [1]. The same review reported that post-treatment complications included pressure sores, infection, and motor deficits, though detailed complication rates were not systematically quantified [1].

In sub-Saharan Africa, complication rates after spine surgery are often higher than in high-income countries, reflecting delayed presentation, limited resources, and higher baseline comorbidity burdens [5]. A study from Tanzania reported that in-hospital complication rates following traumatic spinal injury were 52.9%, predominantly pressure ulcers and paralytic ileus [6]. Delayed surgery and older age have been identified as predictors of complications after spinal trauma in LMICs [6]. A study from Yemen found that neurological complications (10%) and surgical site infections (6%) were the most frequent early complications following posterior lumbar transpedicular screw fixation, with preoperative limb weakness and multilevel fixation associated with higher complication risk [7]. A 10-year review from Nigeria reported surgical site infection rates of 4.0% in spine surgery, with risk factors including hypertension, prolonged hospitalisation, longer operative time, blood transfusion, and higher ASA score [8].

The Nigerian diagnostic imaging landscape and surgical capacity are characterised by significant disparities, with limited access to intraoperative technology, low follow-up rates, and minimal physiotherapy and rehabilitation capabilities [9]. A study from Cambodia highlighted that many factors play a role in spine surgery complications in LMICs, including limited access to intra-operative technology, low follow-up rates, and minimal physiotherapy and rehabilitation capabilities [9].

Despite the growing volume of spinal surgery in Nigeria, comprehensive multicenter data on complication rates and predictive factors are lacking. This multicenter study aimed to appraise the spectrum, frequency, and predictors of complications following spinal surgeries across four tertiary centres in Nigeria.

This multicenter study provides the first comprehensive appraisal of complications following spinal surgery across multiple centres in Nigeria. The overall complication rate of 18.5% is consistent with the range of 10% - 40% reported in international literature [10] and comparable to the 16.7% reported in other LMIC settings [11].

SSI was the most common complication (5.6%), higher than the 2% - 3% reported in many high-income series [12] but similar to rates reported from other LMICs. A 10-year review from Nigeria reported SSI rates of 4.0% in spine surgery [12]. The higher rate in our cohort may reflect patient and institutional factors. While we did not measure theatre ventilation, reusable instrument practices, or contamination directly, the high proportion of trauma patients (38.4%) and the presence of open wounds in some cases may contribute. The predominance of SSI in infection cases (7.8%) and lumbosacral procedures (6.4%) underscores the importance of enhanced infection control protocols.

Dural tear occurred in 3.9% of patients, within the 2% - 5% reported range for posterior spinal surgery [13]. The higher rate in cervical surgeries (5.1%) compared with thoracic (2.8%) and lumbosacral (3.7%) reflects the more complex anatomy and greater risk of incidental durotomy during cervical decompression. The predominance of dural tears in degenerative cases (4.6%) likely reflects the higher proportion of decompression procedures in this group.

Pressure ulcers occurred in 2.8% of patients, lower than the 27.5% reported in a Tanzanian study of traumatic spinal injury [6]. This difference may reflect the inclusion of elective surgeries in our cohort, where patients are generally more stable and have shorter hospital stays. However, the 3.7% rate in trauma patients highlights the need for enhanced pressure ulcer prevention protocols. We did not systematically measure the use of pressure-relieving mattresses or turning protocols in our cohort, which limits causal attribution.

Neurological deterioration occurred in 2.2% of patients, consistent with the 1% - 3% reported in international series [14]. The higher rate in trauma patients (2.9%) likely reflects the severity of injury and the presence of pre-existing neurological deficits.

Implant failure occurred in 1.6% of patients, comparable to the 2% - 5% reported in systematic reviews [15]. All failures occurred in patients who had undergone stabilisation procedures, with a higher rate in thoracic (2.8%) and trauma (2.0%) patients. This may reflect the biomechanical demands of thoracic instrumentation and the high-energy nature of traumatic injuries. Implant failure was assessed at 12-month follow-up (range 6 - 24 months), which may have captured late complications that would not be identified within a 30-day window.

The mortality rate of 0.6% is comparable to rates reported in high-income countries (0.5% - 1.5%) for spinal surgery [16]. The higher mortality in trauma patients (0.8%) and infection cases (1.1%) reflects the greater severity of illness in these groups. A systematic review of traumatic spine injuries in Africa reported a mortality rate of 16.9% in West Africa [17], though this included all spinal injuries, not just surgical patients.

The identification of emergency surgery, thoracic-level surgery, trauma indication, and multilevel fusion as independent predictors of complications is consistent with the literature. Emergency surgery (OR 2.6) is associated with less time for preoperative optimisation and greater physiological stress. The variable remained significant after adjustment for age, comorbidities, and other confounders. Thoracic-level surgery (OR 2.2) reflects the biomechanical complexity and proximity to vital structures. Trauma indication (OR 2.0) is associated with higher-energy injuries, contamination, and pre-existing deficits. Multilevel fusion (OR 1.8) imposes greater biomechanical stress and longer operative time.

Strengths of this study include the multicenter design (enhancing generalizability) and the large sample size (638 patients). However, limitations exist. The retrospective design introduces selection and information bias. The lack of standardised complication definitions across centres may have led to under-reporting. The study did not capture long-term complications beyond 12 months. The single-country design may limit generalizability to other LMICs. The prespecified model excluded some potential confounders (e.g., ASA grade, surgical approach) that were not consistently recorded across centres, which may have introduced residual confounding.

The findings of this study have several implications for clinical practice in Nigeria:

1) Enhanced infection control: Preoperative chlorhexidine bathing, appropriate antibiotic prophylaxis, and meticulous wound closure should be prioritised.

2) Pressure ulcer prevention: Early mobilization, pressure-relieving mattresses, and regular turning protocols are essential, particularly for trauma patients.

3) Risk stratification: Emergency surgery, thoracic-level surgery, trauma indication, and multilevel fusion should be recognised as high-risk factors.

4) Perioperative optimisation: Patients with trauma and infection should be optimized before surgery where possible.

In conclusion, complications following spinal surgery in Nigeria occur in nearly one in five patients, with surgical site infection being the most common. Emergency surgery, thoracic-level surgery, trauma indication, and multilevel fusion are independent predictors of complications. The mortality rate of 0.6% is acceptable and comparable to international benchmarks. Targeted preventive strategies and enhanced perioperative care are urgently needed to reduce the burden of complications and improve patient outcomes in Nigerian spinal surgery.