Suction/irrigation for deep wound infection after spinal instrumentation: a case study

Delayed Infection 34 Months After IntraSPINE® Dynamic Internal Insertion

Introduction

Postoperative surgical site infection remains one of the major complications after spinal surgery. IntraSPINE^® (intraspine) is a dynamic intralaminar device introduced by Cousin Biotech and is indicated for the surgical treatment of lumbar spine disorders. There are no reports on delayed surgical site infection (SSI) after lumbar surgery using this device.

Case Presentation

A 29-year-old male patient was admitted to our department with complaints of moderate pain and chronic subcutaneous abscess with purulent flow from his old surgical scar. Thirty-four months ago, he underwent a traditional open bilateral L4 laminotomy without discectomy and intraspine insertion for the treatment of L4-5 central lumbar spinal stenosis at another hospital. The patient was discharged 4 days after surgery without radiating pain, and the surgical wound was well healed. He gradually returned to his normal activity and work. However, he experienced moderate pain, redness and swelling of his old surgical scar approximately one month before coming to our hospital, but he did not receive any treatment. One month later, he had a mass with purulent discharge at the surgical scar site, and he visited our hospital on December 29th, 2020. Based on the physical examination and MRI findings, delayed -SSI was diagnosed. The patient underwent removal of the intraspine device, debridement and wound closure with closed drainage. The wound healed satisfactorily, and the patient had no complaints more than 2 years later.

Conclusion

A delayed surgical site infection following intraspine insertion may have occurred.

Treatment of distal radius fractures using a cemented K-wire frame

BACKGROUND

This retrospective study included an alternative treatment for types A2, A3, and B1 distal radius fractures using percutaneous fixation with a cemented K-wire frame.

METHODS

From January 2017 to January 2020, 78 patients with distal radius fractures were treated with percutaneous internal fixation using a cemented K-wire frame. There were 47 male patients and 31 female patients. The fractures were classified into types A2 (n = 10), A3 (n = 46), and B1 (n = 22). X-rays were taken immediately after surgery and after the bone had healed. Wrist function was assessed using the Mayo Wrist Score (90-100, excellent; 80-90, good; 60-80, satisfactory; < 60, poor). Patient satisfaction was assessed using the 10-cm visual analog scale.

RESULTS

Neither fixation failure nor K-wire migration was found (P > 0.05). Osteomyelitis was not observed in this series. All patients achieved bone healing after a mean of 4.5 weeks (range, 4 to 8 weeks). Follow-up lasted a mean of 27 months (range, 24 to 33 months). The mean score of wrist function was 97 (range, 91 to 100). Among them, 66 results were excellent and 12 results were good. The mean patient satisfaction was 10 cm (range, 8 to 10 cm).

CONCLUSIONS

Percutaneous fixation with cemented K-wire frame is a safe and preferred choice for the treatment of types A2, A3, and B1 distal radius fractures. The frame provides support to prevent wire migration. The fixation technique is a minimally invasive procedure that is easy to perform.

LEVEL OF EVIDENCE

Therapeutic study, Level IVa.

Management of Postoperative Discitis: A Review of 31 Patients

BACKGROUND

The aim of the study was to retrospectively evaluate the outcome of medical management of postoperative discitis (POD).

MATERIALS AND METHODS

A total of 31 patients treated for POD were included in the study. Clinical, radiological, and laboratory data of all patients were collected and evaluated. All patients were treated initially with bed rest and antibiotic therapy after radiological diagnosis. Surgical management was undertaken after failure of 4 weeks of conservative management. All cases were followed clinically with laboratory and radiological investigations.

RESULTS

Five cases failed to respond to medical management and were treated surgically with debridement and transpedicular fixation. All patients showed clinical recovery till the last follow-up.

CONCLUSION

Early diagnosis and proper management are the keys to successful outcome of postoperative spndylodiscitis. Surgical debridement and fusion are required when conservative treatment fails.

A comparison of minimally invasive approach vs conventional approach for volar plating of distal radial fractures

Background

The aim of this study was to introduce and to evaluate the functional results of volar plating of distal radial fractures through a longitudinal minimally invasive approach.

Methods

From January 2010 to January 2013, 157 patients with distal radial fractures were randomly allocated to group A (n = 83; 49 men, 34 women; mean age: 42 (18–67)) and B (n = 74; 46 men, 28 women; mean age: 41 (22–65)), including type A2, A3, B3, C1, and C2 fractures, based on AO Foundation and Orthopaedic Trauma Association Classification. Patients in group A were treated through a 1.5- to 2-cm longitudinal incision, and patients in group B were treated through the conventional flexor carpi radialis approach. All fractures were treated with a locking volar plate. The functional results were compared with range of motion, grip and pronation strengths for each fracture type.

Results

After a follow-up of 2 years, similar measurements were noted on range of motion and grip strength in both groups. Regarding pronation strength, group A was superior to group B (p < 0.05).

Conclusions

Minimally invasive volar plating of distal radial fractures is a safe and reliable technique, resulting in better pronation function and appearance.

Level of Evidence

Level I, Therapeutic study

Infection with spinal instrumentation: Review of pathogenesis, diagnosis, prevention, and management

Background:

Instrumentation has become an integral component in the management of various spinal pathologies. The rate of infection varies from 2% to 20% of all instrumented spinal procedures. Every occurrence produces patient morbidity, which may adversely affect long-term outcome and increases health care costs.

Methods:

A comprehensive review of the literature from 1990 to 2012 was performed utilizing PubMed and several key words: Infection, spine, instrumentation, implant, management, and biofilms. Articles that provided a current review of the pathogenesis, diagnosis, prevention, and management of instrumented spinal infections over the years were reviewed.

Results:

There are multiple risk factors for postoperative spinal infections. Infections in the setting of instrumentation are more difficult to diagnose and treat due to biofilm. Infections may be early or delayed. C Reactive Protein (CRP) and Magnetic Resonance Imaging (MRI) are important diagnostic tools. Optimal results are obtained with surgical debridement followed by parenteral antibiotics. Removal or replacement of hardware should be considered in delayed infections.

Conclusions:

An improved understanding of the role of biofilm and the development of newer spinal implants has provided insight in the pathogenesis and management of infected spinal implants. This literature review highlights the mechanism, pathogenesis, prevention, and management of infection after spinal instrumentation. It is important to accurately identify and treat postoperative spinal infections. The treatment is often multimodal and prolonged.

Postoperative infection treatment score for the spine (PITSS): construction and validation of a predictive model to define need for single versus multiple irrigation and debridement for spinal surgical site infection

BACKGROUND CONTEXT

There is very little evidence to guide treatment of patients with spinal surgical site infection (SSI) who require irrigation and debridement (I&D) in deciding need for single or multiple I&Ds or more complex wound management such as vacuum-assisted closure dressing or soft-tissue flaps.

PURPOSE

The purpose of this study was to build a predictive model that stratifies patients with spinal SSI, allowing us to determine which patients will need single versus multiple I&D. The model will be validated and will serve as evidence to support a scoring system to guide treatment.

STUDY DESIGN

A consecutive series of 128 patients from a tertiary spine center (collected from 1999 to 2005) who required I&D for spinal SSI were studied based on data from a prospectively collected outcomes database.

METHODS

More than 30 variables were identified by extensive literature review as possible risk factors for SSI and tested as possible predictors of risk for multiple I&D. Logistic regression was conducted to assess each variable's predictability by a "bootstrap" statistical method. A prediction model was built in which single or multiple I&D was treated as the "response" and risk factors as "predictors." Next, a second series of 34 different patients meeting the same criteria as the first population were studied. External validation of the predictive model was performed by applying the model to the second data set, and predicted probabilities were generated for each patient. Receiver operating characteristic curves were constructed, and the area under the curve (AUC) was calculated.

RESULTS

Twenty-four of one hundred twenty-eight patients with spinal SSI required multiple I&D. Six predictors: anatomical location, medical comorbidities, specific microbiology of the SSI, the presence of distant site infection (ie, urinary tract infection or bacteremia), the presence of instrumentation, and the bone graft type proved to be the most reliable predictors of need for multiple I&D. Internal validation of the predictive model yielded an AUC of 0.84. External validation analysis yielded AUC of 0.70 and 95% confidence interval of 0.51 to 0.89. By setting a probability cutoff of .24, the negative predictive value (NPV) for multiple I&D was 0.77 and positive predictive value (PPV) was 0.57. A probability cutoff of .53 yielded a PPV of 0.85 and NPV of 0.46.

CONCLUSIONS

Patients with positive methicillin-resistant Staphylococcus aureus culture or those with distant site infection such as bacteremia were strong predictors of need for multiple I&D. Presence of instrumentation, location of surgery in the posterior lumbar spine, and use of nonautograft bone graft material predicted multiple I&D. Diabetes also proved to be the most significant medical comorbidity for multiple I&D. The validation of this predictive model revealed excellent PPV and good NPV with appropriately chosen probability cutoff points. This study forms the basis for an evidence-based classification system, the Postoperative Infection Treatment Score for the Spine that stratifies patients who require surgery for SSI, based on specific spine, patient, infection, and surgical factors to assess a low, indeterminate, and high risk for the need for multiple I&D.

Infections in spinal instrumentation

Surgical-site infection (SSI) in the spine is a serious postoperative complication. Factors such as posterior surgical approach, arthrodesis, use of spinal instrumentation, age, obesity, diabetes, tobacco use, operating-room environment and estimated blood loss are well established in the literature to affect the risk of infection. Infection after spine surgery with instrumentation is becoming a common pathology. The reported infection rates range from 0.7% to 11.9%, depending on the diagnosis and complexity of the procedure. Besides operative factors, patient characteristics could also account for increased infection rates. These infections after instrumented spinal fusion are particularly difficult to manage due to the implanted, and possibly infected, instrumentation. Because the medical, economic and social costs of SSI after spinal instrumentation are enormous, any significant reduction in risks will pay dividends. The goal of this literature review was to analyse risk factors, causative organisms, diagnostic elements (both clinical and biological), different treatment options and their efficiency and consequences and the means of SSI prevention.

Retrospective study of deep surgical site infections following spinal surgery and the effectiveness of continuous irrigation

Surgical site infection (SSI) is an unfortunate and unpreventable complication of any surgical intervention including spinal surgery. Early deep SSI (EDSSI) after instrumented spinal fusion are particularly difficult to manage due to the implanted, and possibly infected, instrumentation. The purpose of this study is to retrospectively review patients who underwent spinal surgery, investigate the rate of EDSSI, identify patient-related and surgery-related risk factors and to assess the effectiveness of continuous indwelling irrigation on the eradication of these infections. A total of 814 patients (319 women and 495 men) who underwent spinal surgery were enrolled. Mean age at the initial surgery was 57.4 years old. Infections that penetrated the deep fascia within 1 month after the initial operation were considered as EDSSI. The rate of EDSSI, causal organisms, infection management and resolution were studied. Furthermore, we examined the patient-related and the operation-related risk factors. An overall incidence of EDSSI of 1.1% was found. In 177 patients with diabetes mellitus (DM), two patients (1.1%) developed EDSSI. In 28 patients receiving chronic haemodialysis (HD), two patients with infections (7.1%) were identified, which was statistically significantly greater than the other patient populations. Both operative time and intraoperative blood loss were significantly greater in patients with EDSSI than in non-infected patients. Furthermore, the rate of EDSSI in patients undergoing instrumented spinal fusion (3.8%) was significantly higher than that in the other patients. In the nine patients who developed EDSSI, the causal organisms were identified and treated by surgical debridement, antibiotic therapy and continuous indwelling surgical site irrigation. All infections resolved, and no recurrence has been observed at final follow-up. Removal of the instrumentation was required in only one patient. Based on our results, we believe that continuous surgical site irrigation is an effective adjunct in the surgical treatment for early SSI following spinal surgery.

The presentation, incidence, etiology, and treatment of surgical site infections after spinal surgery

STUDY DESIGN

Descriptive, retrospective cohort analysis.

OBJECTIVE

To evaluate the presentation, etiology, and treatment of surgical site infections (SSI) after spinal surgery.

SUMMARY OF BACKGROUND DATA

SSI after spine surgery is frequently seen. Small case control studies have been published reporting the results of treatment options of SSI. We performed this study to identify the most common clinical and laboratory presentation of a SSI, the most frequently seen infective organism, and evaluate the effectiveness of current treatment.

METHODS

All patients who underwent spinal surgery at our institution for diagnosis other than infection between June 1996 and December 2005 (N=3174) were reviewed. All cases of SSI were identified. Patient and operative characteristics were reviewed. Infection type (deep or superficial), treatment course, laboratory and culture results were abstracted.

RESULTS

A total of 132 cases of SSI (84 deep and 48 superficial) were identified. About 72.7% of the SSI were detected as outpatients an average 28.7 days (deep, 29.9; superficial, 25.2) after the index procedure. Wound drainage was the most common complaint (68.2%). C-reactive protein level was elevated in 98.0%, erythrocyte sedimentation rate was elevated in 94.4%, but only 48.6% had elevated white blood cell count. Staphylococcus aureus was isolated in 72.6% of deep and 85.7% of superficial positive cultures. Seventy-six percent of deep SSI could be treated with a single debridement to clear the SSI. Instrumentation was retained or primarily exchanged if loose in all cases. Around 72.9% of superficial SSI were treated without formal debridement in the operating room. Antibiotic treatment was longer in deep SSI (40.8 vs. 19.6 days).

CONCLUSION

Deep SSI following spinal surgery was effectively treated with single stage debridement and intravenous antibiotics. Superficial SSI could be treated effectively with local wound care and oral antibiotic therapy.

Closed suction irrigation for the treatment of postoperative wound infections following posterior spinal fusion and instrumentation

STUDY DESIGN

Retrospective review of clinical cases.

OBJECTIVE

This study describes the success rate of closed suction irrigation system (CSIS) in the treatment of post operative spinal infections.

SUMMARY OF BACKGROUND DATA

Given the widening use of spinal instrumentation, the management of related postoperative deep wound infections has become increasingly important. In the literature, there have been reports of several treatment methods yet no firmly established protocol for management of postoperative deep wound infections exists. The goal of this study was to determine the effectiveness of our protocol employing (CSIS) in the treatment of postoperative deep wound infections.

METHODS

A retrospective record review of 500 posterior instrumented fusions between 1990 and 2002. Twenty-eight consecutive infections (5%) were diagnosed and treated by a standardized treatment protocol of Incision and Drainage, and CSIS. Cultures were obtained, wounds closed primarily, and appropriate intravenous antibiotic treatments initiated. For statistical evaluation, patients were assigned a risk factor (RF) described by Levi et al (J Neurosurg. 1997;86:975-980). Point values were assigned to medical comorbidities that may contribute to postoperative infection risk; higher RF values indicate an increased risk.

RESULTS

Twenty-one acute and 7 late (>6 months) infections were followed for 22.3 months (1-86 months), post-CSIS treatment. Twenty-one (75%) resolved without recurrence with one CSIS treatment. Seven acute infections (25%) required a second course of treatment. Hospitalization for the index procedure averaged 15.4 days; 28.9 days for reinfections. No patient with an acute infection required implant removal. The reinfection group had higher blood loss, more levels fused, and longer hospitalization. The reinfection group was comprised entirely of pediatric patients.

CONCLUSION

No correlation was found between RF values and greater risk of recurrent infection. Removal of implants is unnecessary in acute infections, provided the infection does not return. CSIS is an effective method for treatment of postoperative wound infections following instrumented spinal fusion avoiding the need for secondary closure.

Evolução clínica e funcional dos pacientes com infecção após artrodese de coluna lombar

OBJETIVOS: descrever a experiência dos autores no manejo da infecção após instrumentação da coluna lombar e suas consequências futuras. MÉTODOS: estudo de coorte prospectivo com pacientes portadores de infecção profunda pós-operatória, realizado entre janeiro de 1997 e janeiro de 2009. Todos os pacientes foram submetidos à revisão cirúrgica, coleta de material para exame microbiológico, lavagem exaustiva da região, debridamento dos tecidos desvitalizados, colocação de sistema de lavagem contínua, sutura primária e antibioticoterapia. Manteve-se a instrumentação em todos os pacientes. Os pacientes foram avaliados durante o seguimento por imagens radiográficas, estado clínico e funcional. Utilizaram-se a escala numérica da dor e o índice de incapacidade Oswestry. Os resultados numéricos foram submetidos a análises pareadas pelo teste de Wilcoxon. RESULTADOS: a incidência de infecção foi de 3,1% (15/485). O agente etiológico mais prevalente foi o Staphylococcus aureus. Todos os casos lograram consolidação. Em um seguimento médio de 47,6 meses, observaram-se mudanças nos escores da escala numérica da dor (p=0,001) e índice de incapacidade Oswestry (p=0,017). Na avaliação final, 64,2% dos pacientes (9/14) apresentaram incapacidade mínima e 35,8% (5/14), incapacidade moderada. CONCLUSÃO: o tratamento agressivo das infecções pós-operatórias de artrodese de coluna lombar permite evitar a retirada da instrumentação e manter a estabilidade vertebral. A despeito da complicação, os pacientes apresentaram melhoras em relação à dor e capacidade funcional pré-operatórias.

Deep brain stimulator hardware-related infections: incidence and management in a large series

OBJECTIVE

Device-related infection is a common complication of deep brain stimulator (DBS) implantation. We reviewed the incidence and management of early hardware-related infections in a large series.

METHODS

All patients undergoing DBS implantation surgery between 1998 and 2006 at a single institution were entered into a prospectively designed database. After database verification by cross-referencing manufacturer implantation records, a query was performed to include all new Medtronic (Minneapolis, MN) implantations performed with standard operating room technique. Hardware-related infections requiring further surgery were identified, and charts were reviewed to assess the success of lead-sparing partial hardware removal in this group.

RESULTS

Four hundred twenty patients received 759 new DBS electrodes and 615 new internal pulse generators for the treatment of movement disorders or pain. Nineteen patients (4.5%) had an early (<6 mo) hardware-related infection requiring further surgery. There were no intracranial infections. Four patients presented with extensive cellulitis or wound dehiscence and were treated with total hardware removal. Fourteen patients presented with more localized infections and were treated by removal of the involved components only, followed by intravenously administered antibiotics. In nine of these patients, partial hardware removal successfully resolved the infection without requiring removal of the DBS electrodes. Wound washout alone was attempted in one patient and failed.

CONCLUSION

In a large series of new DBS hardware implantations, the incidence of postoperative hardware-related infection requiring further surgery was 4.5%. When only one device component was involved, partial hardware removal was often successful.

[Management of deep wound infections in spinal lumbar fusions]

The rate of deep wound infections in spinal lumbar fusions is around 0.7% to 11.6%, being one of the causes of morbidity in acute phase. The aim of this study was to evaluate the management of spinal infection after internal lumbar fusions. Two hundred and sixty patients, who underwent to spinal surgery with lumbar fusion and iliac bone grafting, were analized, from January 1997 to January 2005. Wound infection was observed in eight (3%) cases. The average of age was 56 years, with a higher prevalence in males (5 patients). Most prevalent was Staphylococcus aureus in 6 patients. The treatment was done by intravenous antibiotic therapy folowed by oral therapy and local irrigation. The average time of hospitalization was 35.8 days. It was possible to erradicate infection without removal of instrumentation in all patients.

Wound conditioning by vacuum assisted closure (V.A.C.) in postoperative infections after dorsal spine surgery

The use of vacuum assisted closure (V.A.C.) therapy in postoperative infections after dorsal spinal surgery was studied retrospectively. Successful treatment was defined as a stable healed wound that showed no signs of acute or chronic infection. The treatment of the infected back wounds consisted of repeated debridement, irrigation and open wound treatment with temporary closure by V.A.C. The instrumentation was exchanged or removed if necessary. Fifteen patients with deep subfascial infections after posterior spinal surgery were treated. The implants were exchanged in seven cases, removed completely in five cases and left without changing in one case. In two cases spinal surgery consisted of laminectomy without instrumentation. In two cases only the wound defects were closed by muscle flap, the remaining ones were closed by delayed suturing. Antibiotic treatment was necessary in all cases. Follow up was possible in 14 patients. One patient showed a new infection after treatment. The study illustrates the usefulness of V.A.C. therapy as a new alternative management for wound conditioning of complex back wounds after deep subfascial infection.

The use of a sump antibiotic irrigation system to save infected hardware in a patient with a vagal nerve stimulator

The authors describe the use of a sump irrigation system that was used to successfully treat the battery implantation site of a vagal nerve stimulator (VNS). Irrigation was composed of a dilution of vancomycin in lactated Ringer's solution. At long-term follow up, the patient has not returned with signs or symptoms of wound infection. She continues to effectively combat her epilepsy with VNS. The authors believe this to be the first description of this technique for salvaging an implanted VNS.

Late implant infections caused by Propionibacterium acnes in scoliosis surgery

One hundred and one consecutive adolescent scoliosis patients instrumented from the posterior between 1995 and 2002, with a minimum follow-up of 24 months (maximum 106 months), were reviewed for incidence of infection. Stainless steel implants with pedicle screws were used in the thoracic and lumbar spine of all patients. All were operated on by a single surgeon. There were no early infections. Incidence of late infection was 6.9% (seven patients). Clinical indicators for infection were the sudden onset of local pain and swelling without fever after an initial pain-free interval. There were no reliable laboratory parameters. Normal CRP and ESR did not rule out a late infection. Extended cultures were done from intraoperative swabs. Propionibacterium acnes was found in six patients. There were no other organisms identified. No causative organism could be identified in one patient, despite extended cultures. All patients were successfully treated with implant removal and antibiotic therapy for 4-9 weeks. No pseudarthrosis was seen on implant removal. Despite bony fusion, loss of correction between 10 degrees and 26 degrees was observed in three patients after implant removal.

[Osteomyelitis of the spine]

Spinal infections are rare, occurring most often in elderly patients with urinary tract infections or diabetes. With the increasing number of patients with immune suppression, and also the increasing number of immigrants in the population, spinal infections are seen more frequently, especially in young adults. Typically spinal infections are monomicrobial, Staphylococcus aureus being the most common organism. Hematogenous spread of bacteria through the arterial paravertebral collateral vessels into the subchondral bone marrow of the vertebral bodies is the most common source of infection. Clinical presentation is often nonspecific. Important diagnostic measurements are laboratory studies, radiological evaluation including MR image scans, and CT-guided percutaneous biopsy of the lesion for microbiological studies. The management of spinal infections consists of antimicrobial therapy over 6-8 weeks. Surgical intervention is indicated in neurologically compromised patients for spinal instability and abscesses.

Rotational and transpositional flaps for the treatment of spinal wound dehiscence and infections in patient populations with degenerative and oncological disease

OBJECT

Wound-related complications following complex posterior spine procedures may result in the need for serial debridements and may place the instrumentation at risk. Numerous treatments have been advocated for this problem, but each has limitations. In this article the authors discuss the experience from two large teaching institutions at which rotational and transpositional flaps were used in the management of deep wound infections and dehiscences.

METHODS

The authors generated a list of patients treated via posterior or posterolateral approaches for metastatic tumors or complex degenerative disorders in whom wound complications subsequently developed. Data were obtained from the medical records and reviewed retrospectively. Thirty-seven patients were treated with rotational or transpositional flaps at the two institutions during the study period. Patients underwent a mean of 1.3 procedures for the treatment of wound healing problems, and cultures were positive in 70%. In three patients (8%) this treatment failed due to protrusion of hardware through the skin or repeated dehiscence requiring reclosure. Spinal instrumentation was salvaged in 97% of the cases.

CONCLUSIONS

The use of local tissue flaps is advantageous for treatment of posterior wound complications due to spine surgery. In this procedure highly vascularized tissue is used to increase healing, accelerate clearance of bacteria, and fill any dead space.

Delayed infection after instrumented spine surgery: case reports and review of the literature

BACKGROUND CONTEXT

A delayed infection after instrumented spine surgery can be difficult to diagnose because of its low incidence and variety of clinical symptoms.

PURPOSE

To describe four cases of delayed infection after instrumented spine surgery and to review the literature of such cases with regard to the clinical symptoms and risk factors, possible causes of infection and treatment.

STUDY DESIGN/SETTING

Personal review of cases and literature review.

PATIENT SAMPLE

Four cases in this report and 93 other cases reported in the literature.

OUTCOME MEASURES

Not measured.

METHODS

Summary of the clinical symptoms, risk factors, causes of infection and treatment regimens.

RESULTS

Three possible causes of a delayed infection have been cited: intraoperative seeding, metal fretting causing a sterile inflammatory response or stimulating low-virulent organisms to fester and hematogenous seeding. A variety of clinical symptoms were found, but spontaneous drainage appears to be most common. Many patients had either a fluctuant mass, localized drainage or an abscess. Abscesses or drainage material is typically contiguous with the instrumentation and the fusion mass. Fever was present in only six patients. Effective treatment usually includes removal of the implants, irrigation and debridement, followed by the administration of antibiotics.

CONCLUSIONS

A high level of suspicion is needed to diagnose a delayed infection after instrumented spine surgery.

Postoperative spinal wound infection: a review of 2,391 consecutive index procedures

Postoperative infection remains a troublesome but not uncommon complication after spinal surgery. Most previous reports, however, are small or involve cases with more than one surgeon often at different institutions. This study represents a single surgeon's 9-year experience with postoperative infection at one institution. The authors describe the features of wound infection after spinal surgery with reference to diagnosis, microbiology, and treatment and they describe a protocol for effective management of postoperative spinal wound infection. The records of the senior author (F.P.C.) during a 9-year period for cases of postoperative wound infection were reviewed. Of 2,391 operative procedures, 46 cases of wound infection were identified, yielding an overall infection rate of 1.9%. Patients' preoperative risk factors, original diagnosis prompting the surgery, onset of infection, presentation, treatment, and outcome were analyzed. The mean age of the 23 men and 23 women was 57.2 years. The preoperative diagnoses included lumbar degenerative scoliosis or spinal stenosis in 28 cases, disk prolapse in 8 cases, metastatic disease in 4 cases, degenerative disk disease in 1 case, and a group of 5 miscellaneous cases. Seventeen (37%) of the patients underwent at least one previous spinal surgery at the same site. Twenty-three patients had a fusion, of whom 22 also had instrumentation. Forty-three (93%) of the patients had significant wound drainage after an average of 15 days (range, 5-80 days). The other three patients were examined approximately 2 years after the surgery. Fourteen of the patients also had pyrexia (temperature >37.5 degrees C) at presentation. Staphylococcus aureus alone was cultured in 29 patients, whereas another six patients had a different single organism. In nine patients, more than one organism was cultured during their hospital stay. Surgical treatment included primary closure in only seven patients, with most undergoing wound drainage and debridement followed by delayed closure. Instruments were removed in the three patients with late presentation who had solid fusion at operation. Viable bone graft and instrumentation were left in situ in all patients who were seen before fusion. All wounds healed without sequelae, except for three that required flap closure. Pseudarthrosis was noted in three patients after more than 1 year of follow-up in this series. Postoperative spinal wound infection is a potentially devastating problem. In this series, infection was more common in patients undergoing fusion with instrumentation and in patients with cancer metastatic to the spine. An aggressive surgical approach, including repeated debridement followed by delayed closure, is justified. Instrumentation may be safely left in situ to provide stability for fusion.