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Surgical complications associated with hemilaminectomy and intervertebral disc fenestration: Prospective study of 64 dogs

Complicações associadas à hemilaminectomia toracolombar e fenestração de disco intervertebral: estudo prospectivo em 64 cães

ABSTRACT:

Hemilaminectomy and intervertebral disc fenestration are commonly used to treat intervertebral disc extrusion (IVDE); however, they are associated with surgical complications. Sixty-four dogs were assessed during the intraoperative, immediate postoperative, and late postoperative periods to evaluate complications resulting from these surgical procedures. During this study, 15.62% (n=10) of the dogs presented with complications during at least one of the evaluations. Iatrogenic rhizotomy, access to the spinal canal contralateral to the lesion, and cardiorespiratory arrest were observed intraoperatively. Abdominal wall flaccidity, neurological worsening, hematoma, dehiscence, and superficial wound infections were observed during the immediate postoperative period. Adverse reactions to the surgical thread, scar adhesion, and superficial wound infection were the most frequent complications during the late postoperative period. Dogs that undergo hemilaminectomy and intervertebral disc fenestration because of IVDE may experience complications during the intraoperative, immediate postoperative, and late postoperative periods. However, these complications are often transitory and rarely cause death.

Key words:
herniated disc; intervertebral fenestration; spinal decompression; intervertebral disc extrusion complications

RESUMO:

A hemilaminectomia e a fenestração do disco intervertebral são os procedimentos cirúrgicos geralmente empregados no tratamento da extrusão do disco intervertebral (EDIV), os quais podem desencadear complicações cirúrgicas. Foram avaliadas complicações em 64 cães nos períodos intra e pós-operatório imediato e tardio. Dos pacientes incluídos no estudo, 15,62% (n=10) apresentaram alguma ocorrência em pelo menos uma das etapas avaliadas. Das complicações, no período intraoperatório foram observadas rizotomia iatrogênica, abertura do canal vertebral contralateral e parada cardio-respiratória. No pós-operatório imediato foram verificadas a flacidez da parede abdominal lateral, piora neurológica, hematoma, deiscência de ferida cirúrgica e infecção superficial da ferida de pele. No pós-operatório tardio foram verificadas reação ao fio cirúrgico, aderência cicatricial e flacidez da parede abdominal lateral como problemas mais frequentes. Conclui-se que cães submetidos à hemilaminectomia e fenestração do disco intervertebral envolvido em decorrência da EDIV podem apresentar complicações nos períodos intraoperatório, pós-operatório imediato e tardio, sendo transitórias e com mínimas chances de ocasionar óbito.

Palavras-chave:
hérnia discal; fenestração intervertebral; descompressão medular; extrusão de disco intervertebral; complicações

INTRODUCTION:

Intervertebral disc extrusion (IVDE) (Hansen type I) is considered one of the main causes of compressive injuries of the spinal cord in dogs (BERGKNUT et al., 2012BERGKNUT, N. et al. Incidence of intervertebral disk degeneration-related disease and associated mortality rates in dogs. Journal of American Veterinary Medicine Association, v.240, n.11, p.1300-1309, 2012. Available from: <Available from: https://pubmed.ncbi.nlm.nih.gov/22607596 >. Accessed: Nov. 11, 2021. doi: 10.2460/javma.240.11.1300.
https://pubmed.ncbi.nlm.nih.gov/22607596...
; DEWEY & DA COSTA, 2016DEWEY, C. W.; DA COSTA, R. C. Myelopathies: disorders of the spinal cord. In: DEWEY, C.W.; DA COSTA, R.C. Practical guide to canine and feline neurology. 3. ed. Iowa: Wiley Blackwell, 2016. Cap13, p.329-406.; MOORE et al., 2020MOORE, S. A., et al. Current approaches to the management of acute thoracolumbar disc extrusion in dogs. Frontiers in Veterinary Science, v.7, p.1-15, 2020. Available from: <Available from: https://www.frontiersin.org/articles/10.3389/fvets.2020.00610 >. Accessed: Jan. 12, 2021. doi: 10.3389/fvets.2020.00610.
https://www.frontiersin.org/articles/10....
). Clinical signs of injury in the thoracolumbar region vary from spinal hyperesthesia to paraplegia without nociception (MOORE et al., 2020). Surgical treatment is warranted for patients with moderate or severe neurological deficits, patients experiencing relapse, and cases refractory to clinical treatment (DEWEY & DA COSTA, 2016DEWEY, C. W.; DA COSTA, R. C. Myelopathies: disorders of the spinal cord. In: DEWEY, C.W.; DA COSTA, R.C. Practical guide to canine and feline neurology. 3. ed. Iowa: Wiley Blackwell, 2016. Cap13, p.329-406.). Hemilaminectomy and fenestration of the intervertebral disc are the most common treatments for IVDE (BRISSON, 2017BRISSON, B. A. Intervertebral disc fenestration. In: SHORES, A.; BRISSON, B.A (Ed.), Current techniques in canine and feline neurosurgery. 1. ed. New Jersey: Wiley Blackwell, 2017. Cap. 22, p.191-198.; SHORES, 2017SHORES, A. Thoracolumbar hemilaminectomy. In: SHORES, A.; BRISSON, B.A. Current techniques in canine and feline neurosurgery. 1. ed. New Jersey: Wiley Blackwell , 2017. Cap. 20, p.179-182.).

The success of a surgical procedure relies on adequate treatment and patient care during the preoperative, intraoperative, and postoperative periods (LEXMAULOVÁ et al., 2008LEXMAULOVÁ, L. et al. Complications related to surgical treatment of intervertebral disc disease in dogs. Acta Veterinaria Brno, v.77, p.269-276, 2008. Available from: <Available from: https://actavet.vfu.cz/77/2/0269 >. Accessed: Feb. 15, 2020. doi: 10.2754/avb200877020269.
https://actavet.vfu.cz/77/2/0269...
). SHARP & WHEELER (2005SHARP, N. J. H.; WHEELER, S. J. Small animal spinal disorders, diagnosis and surgery. 2. ed. Edinburgh: Elsevier, 2005. 379p.) summarized the main surgical complications after thoracolumbar hemilaminectomies; however, information regarding the incidence and characteristics of the surgical complications associated with hemilaminectomy and fenestration of the intervertebral disc is limited. Therefore, this study identified the main surgical complications during the intraoperative, immediate postoperative, and late postoperative periods that were experienced by dogs diagnosed with IVDE that underwent hemilaminectomy and intervertebral disc fenestration.

MATERIALS AND METHODS:

Dogs of different breeds, different ages, and both sexes with neurological signs attributable to IVDE in the thoracolumbar region that underwent hemilaminectomy and intervertebral disc fenestration performed using techniques described by SHORES (2017SHORES, A. Thoracolumbar hemilaminectomy. In: SHORES, A.; BRISSON, B.A. Current techniques in canine and feline neurosurgery. 1. ed. New Jersey: Wiley Blackwell , 2017. Cap. 20, p.179-182.) and BRISSON (2017BRISSON, B. A. Intervertebral disc fenestration. In: SHORES, A.; BRISSON, B.A (Ed.), Current techniques in canine and feline neurosurgery. 1. ed. New Jersey: Wiley Blackwell, 2017. Cap. 22, p.191-198.) were included in this study. The animals were evaluated during the intraoperative period (from the beginning of surgery [incision] until the last suture was stitched), immediate postoperative period (from the time when the last suture was stitched until 72 h after surgery), and late postoperative period (between 72 h and 30 days after surgery).

Clinical and neurological examinations and laboratory tests (complete blood count, serum biochemistry and electrolyte test, prothrombin time test, and activated partial thromboplastin time test) were performed during the preoperative period. Computed tomography (CT) or myelography was performed to diagnose extramedullary compression caused by IVDE. Neurological dysfunction was classified as follows: grade I, hyperesthesia only; grade II, proprioceptive deficits, ataxia, and ambulatory paresis; grade III, non-ambulatory paresis; grade IV, paraplegia with nociception; and grade V, paraplegia without nociception (SHARP & WHELLER, 2005SHARP, N. J. H.; WHEELER, S. J. Small animal spinal disorders, diagnosis and surgery. 2. ed. Edinburgh: Elsevier, 2005. 379p.).

Hemilaminectomy followed by intervertebral disc fenestration was performed in only one disc space. Surgical complications were considered unwanted events associated with the surgical procedure or occurring during the postoperative period that were confirmed by physical, laboratory, or imaging evaluations. Abnormalities were recorded using specific forms during the intraoperative, immediate postoperative, and late postoperative periods and an interview with the surgeon.

The following information was determined during the intraoperative period: procedure time (min); access to the vertebral canal or intervertebral space in the correct location and on the correct side; intervertebral disc material in the canal after fenestration; pneumothorax; cardiac arrest; iatrogenic injury of the spinal cord; and iatrogenic rhizotomy (SHARP & WHEELER, 2005SHARP, N. J. H.; WHEELER, S. J. Small animal spinal disorders, diagnosis and surgery. 2. ed. Edinburgh: Elsevier, 2005. 379p.; BRISSON, 2017BRISSON, B. A. Intervertebral disc fenestration. In: SHORES, A.; BRISSON, B.A (Ed.), Current techniques in canine and feline neurosurgery. 1. ed. New Jersey: Wiley Blackwell, 2017. Cap. 22, p.191-198.; HETTLICH, 2017HETTLICH, B. Vertebral fracture and luxation repair. In: SHORES, A.; BRISSON, B.A. Current techniques in canine and feline neurosurgery. 1. ed. New Jersey: Wiley Blackwell , 2017. Cap. 25, p.209-222.; SHORES, 2017SHORES, A. Thoracolumbar hemilaminectomy. In: SHORES, A.; BRISSON, B.A. Current techniques in canine and feline neurosurgery. 1. ed. New Jersey: Wiley Blackwell , 2017. Cap. 20, p.179-182.; DIAMANTE et al., 2020DIAMANTE, G. A. C. et al. Long-term clinical complications associated with the use of polymethyl methacrylate in spinal stabilization of dogs and cats: case series. Semina: Ciências Agrárias, v.41, p.2453-2462, 2020. Available from: <Available from: https://www.uel.br/revistas/uel/index.php/semagrarias/article/view/34809 >. Accessed: Sep. 13, 2021. doi: 10.5433/1679-0359.2020v41n5Supl1p2453.
https://www.uel.br/revistas/uel/index.ph...
; MOORE et al., 2020MOORE, S. A., et al. Current approaches to the management of acute thoracolumbar disc extrusion in dogs. Frontiers in Veterinary Science, v.7, p.1-15, 2020. Available from: <Available from: https://www.frontiersin.org/articles/10.3389/fvets.2020.00610 >. Accessed: Jan. 12, 2021. doi: 10.3389/fvets.2020.00610.
https://www.frontiersin.org/articles/10....
).

During the immediate postoperative period, dogs were clinically and neurologically evaluated every 24 h, and the following changes were observed: flaccidity of the abdominal wall; hematoma; systemic or wound infection; suture dehiscence; and worsening of the neurological condition. A hematoma is defined as the accumulation of blood or clots between tissues in the subcutaneous dead space (MANN, 2011MANN, F. A. Surgical tubes and drains. In: MANN, F. A.; CONSTANTINESCU, G. M.; YOON, H. Y. Fundamentals of small animal surgery, 1 ed, Chincheste: Wiley-Blackwell, 2011. Cap. 17, p.208-276.). Flaccidity of the abdominal wall refers to the loss of muscle tone and consequent unilateral or bilateral abdominal bulging (SHARP & WHEELER, 2005SHARP, N. J. H.; WHEELER, S. J. Small animal spinal disorders, diagnosis and surgery. 2. ed. Edinburgh: Elsevier, 2005. 379p.). Surgical wound infection was defined based on the criteria established by the Centers for Disease Control and Prevention (Atlanta, GA, USA). Infections were considered superficial if positive bacterial culture results were observed and if they occurred within 30 days after the procedure, affected only the skin and subcutaneous tissue, and were accompanied by clinical signs of superficial drainage of purulent discharge. All dogs received an intravenous bolus of prophylactic antibiotics (sodium cephalothin 30 mg/kg) 30 min before surgery and every 2 hours thereafter at the same dosage until the end of surgery.

At 1 month after surgery (the late postoperative period), the patients underwent clinical and neurological evaluations. The complications investigated during this evaluation were signs of systemic or surgical wound infection, adverse reactions to the surgical thread, deformities (adhesions of the incision in the subcutaneous tissue and muscular tissue, atrophy of the epaxial muscles, and flaccidity of the abdominal wall), and worsening of the neurological status.

During the preoperative and immediate postoperative periods, the patients were hospitalized in a kennel, housed in individual cages, and treated by the same professionals. Postoperative analgesia was ensured by the administration of methadone (0.3 mg/kg administered subcutaneously [SC] every 4 hours for 24 hours), meloxicam (0.1 mg/kg administered SC for 3 days), and dipyrone sodium (25 mg/kg administered SC every 8 hours for 5 days). Patients were discharged 3 days after surgery.

The results and frequency of changes observed during each evaluation were tabulated and subjected to a descriptive analysis. A statistical analysis using a binomial test was performed to evaluate the significance of each complication. Furthermore, each complication was correlated with sex, age, and weight using the chi-square test, with P < 0.05 indicating significance.

RESULTS AND DISCUSSION:

Sixty-four dogs that underwent hemilaminectomy and fenestration of the intervertebral disc to treat IVDE were included in this study. Of these, 39.06% (n = 25) were male and 60.93% (n = 39) were female. All procedures were performed in the thoracolumbar region (T3 - L3). The mean age, weight, surgical time, and incision size were 5.9 years (standard deviation [SD], ± 1.98 years), 7.85 kg (SD, ± 4.11 kg), 95.55 min (± 30.06 min), and 77.38 mm (± 21.84 mm), respectively. The neurological dysfunction of the 64 dogs was classified as follows: grade II, 1.56% (n = 1); grade III, 6.25% (n = 4); grade IV, 28.13% (n = 18); and grade V, 64.06% (n = 41). No variable (sex, age, weight) significantly influenced the occurrence of complications. Of the 64 patients, 15.62% (n = 10) had at least one complication during at least one of the evaluation periods (Figure 1). The frequency of complications can be explained by the performance of two procedures (hemilaminectomy and fenestration of the intervertebral disc), which increased the probability of complications. The prospective nature of this study, which limited the evaluation methodology, may have contributed to the complication rate, which was higher than that reported by retrospective studies; retrospective studies tend to underestimate the occurrence of complications because the data are not carefully evaluated or recorded (DEKUTOSKI et al., 2010DEKUTOSKI, M. B. et al. Surgeon perceptions and reported complications in spine surgery. Spine Journal, v.35, p.S9-S21, 2010. Available from: <Available from: https://www.ncbi.nlm.nih.gov/pubmed/20407356 >. Accessed: Jun. 12, 2021. doi: 10.1097/BRS.0b013e3181d830de.
https://www.ncbi.nlm.nih.gov/pubmed/2040...
).

Figure 1 -
Surgical complications during the intraoperative, immediate postoperative, and late postoperative periods experienced by dogs with intervertebral disc extrusion that underwent hemilaminectomy and intervertebral disc fenestration. RZ, rhizotomy; CL, contralateral side; CA, cardiac arrest; SI, superficial wound infection; WF, abdominal wall flaccidity; DS, skin suture dehiscence; HT, hematoma; NW, worsening of the neurological status; SA, scar adhesion; RT, adverse reaction to the surgical thread.

During the intraoperative, immediate postoperative, and late postoperative periods, complication rates of 7.81% (n = 5), 10.93% (n = 7 ), and 6.25% (n = 4), respectively, were observed. Of the 64 dogs, only three (4.69%) experienced complications during all periods; two of those dogs experienced iatrogenic rhizotomy during the intraoperative period and flaccidity of the abdominal wall during the immediate postoperative and late postoperative periods. The complications and their frequencies are presented in figure 1. None of the complications caused death. One dog (1.56%) experienced cardiac arrest during surgery; however, satisfactory recovery was achieved after resuscitation.

During the intraoperative period, the opening of the vertebral canal was contralateral to the lesion in two dogs (3.12%). We believed that this complication was not related to the surgical treatment; instead, it likely resulted from erroneous image interpretation attributable to the limitation of myelography for detecting lateralization of compressions, especially in the presence of edema and contrast failure in the subarachnoid space. Oblique projections are necessary for identifying circumferential lesions in the vertebral canal (GIBBONS et al., 2006GIBBONS, S. E.et al. The value of oblique versus ventrodorsalmyelographic views for lesion lateralization in canine thoracolumbar disc disease. Journal of Small Animal Practice., v.47, p.658-662, 2006. Available from: <Available from: https://pubmed.ncbi.nlm.nih.gov/17076789 >. Accessed: Jun. 12, 2021. doi: 10.1111/j.1748-5827.2006.00067.x.
https://pubmed.ncbi.nlm.nih.gov/17076789...
). Such views were used when examining these dogs; however, they were not able to demonstrate lateralization of compressions. CT and magnetic resonance imaging can be used to obtain multiplanar images (ROBERTSON & THRALL, 2011ROBERTSON, I.; THRALL, D. Imaging dogs with suspected disc herniation: pros and cons of myelography, computed tomography, and magnetic resonance. Veterinary Radiology & Ultrasound, v.52, p.S81-S84, 2011. Available from: <Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1740-8261.2010.01788.x >. Accessed: Mar. 12, 2021. doi: 10.1111/j.1740-8261.2010.01788.x.
https://onlinelibrary.wiley.com/doi/full...
).

Postoperative abdominal wall flaccidity may occur as a result of manipulation or sectioning of the nerve roots (rhizotomy) that innervate the abdominal muscles. During this study, four dogs (6.25%) experienced this complication during the immediate postoperative period. Furthermore, two dogs (3.12%) experienced iatrogenic rhizotomy as a result of the attempt to remove the disc material that had adhered to the nerve root; this abnormality persisted during the late postoperative period. In one dog, manipulation of the nerve roots during surgical decompression possibly caused functional loss (neuropraxia) with interruption of the motor pathways; however, this was considered transient because flaccidity was not noted during the late postoperative evaluation. In another dog, flaccidity persisted during the late postoperative period even though complete sectioning of the nerve root was not performed; therefore, the manipulation may have caused a more severe injury. BARTELS et al. (1983BARTELS, K. E. et al. Complications associated with the dorsolateral muscle-separating approach for thoracolumbar disk fenestration in the dog. Journal of the American Veterinary Medical Association, v.183, p.1081-1083, 1983. Available from: <Available from: https://www.ncbi.nlm.nih.gov/pubmed/6643214 >. Accessed: Mar. 07, 2020.
https://www.ncbi.nlm.nih.gov/pubmed/6643...
) reported that abdominal wall flaccidity was observed during the immediate postoperative period in 10% of animals that underwent fenestration; furthermore, this change persisted during the late postoperative period in three animals. For humans, the recovery process can last weeks to months (ASHBY et al., 1974ASHBY, P. et al. Segmental reflex pathways in spinal shock and spinal spasticity in man. Journal of Neurology, Neurosurgery, and Psychiatry, v.31, p.1352-1360, 1974. Available from: <Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1083652 >. Accessed: Jul. 14, 2020. doi: 10.1136/jnnp.37.12.1352.
https://www.ncbi.nlm.nih.gov/pmc/article...
).

Hematomas result from poor physiological or surgical hemostasis (SHARP & WHEELER, 2005SHARP, N. J. H.; WHEELER, S. J. Small animal spinal disorders, diagnosis and surgery. 2. ed. Edinburgh: Elsevier, 2005. 379p.). Only one patient (1.56%) in our study developed a hematoma. That dog did not have a platelet count below the physiological parameters or altered prothrombin time or activated partial thromboplastin time values. Other tests, such as the buccal mucosal bleeding time test and thromboelastography, were not performed. However, coagulopathy that culminated in hematoma formation occurred in this patient. Additionally, it is possible that intraoperative hemostasis failed, thus culminating in hematoma formation during the immediate postoperative period.

During an epidemiological study of wound infections in humans, CRUSE and FOORD (1980) concluded that extensive incisions were associated with a higher risk of contamination by bacteria. Another study also reported an association between long surgical times and surgical wound infections (NICHOLSON et al., 2002NICHOLSON, M. et al. Epidemiologic evaluation of postoperative wound infection in clean-contaminated wounds: a retrospective study of 239 dogs and cats. Veterinary Surgery, v.31, p.577-581, 2002. Available from: <Available from: https://www.ncbi.nlm.nih.gov/pubmed/12415527 >. Accessed: Jun. 20, 2020. doi: 10.1053/jvet.2002.34661.
https://www.ncbi.nlm.nih.gov/pubmed/1241...
), and that the duration of anesthesia may be associated with a deficient immune response. During our study, superficial infection of the surgical wound was observed in only one dog (1.56%) during the immediate postoperative period. However, the incision length and surgical time of that dog were not superior to those of the other dogs in this study.

Prophylactic antibiotics were used for all dogs in this study because their use has been recommended for all procedures lasting longer than 90 min (VASSEUR, 1988VASSEUR, P. B. et al. Surgical wound infection rates in dogs and cats. Data from a teaching hospital. Veterinary Surgery, v.17, p.60-64, 1988. Available from: <Available from: https://www.ncbi.nlm.nih.gov/pubmed/3238876 >. Accessed: Jun. 08, 2020.
https://www.ncbi.nlm.nih.gov/pubmed/3238...
). However, a more recent publication questioned the use of antibiotics for dogs subjected to hemilaminectomy and/or laminectomy because of the low (0.6%) infection rate (DYALL & SCHMÖKEL, 2018DYALL, B. A. R.; SCHMÖKEL H. G. Surgical site infection rate after hemilaminectomy and laminectomy in dogs without perioperative antibiotic therapy. Veterinary and Comparative Orthopaedics and Traumatology, v.31, p.202-213, 2018. Available from: <Available from: https://pubmed.ncbi.nlm.nih.gov/29679951 >. Accessed: Mar. 12, 2020. doi: 10.1055/s-0038-1639365.
https://pubmed.ncbi.nlm.nih.gov/29679951...
). According to another study that used prophylactic antibiotics, the infection rate for dogs that underwent hemilaminectomy and laminectomy was 4.2% (VÄLKKI et al., 2020VÄLKKI, K. H. T. et al. Antimicrobial prophylaxis is considered sufficient to preserve an acceptable surgical site infection rate in clean orthopaedic and neurosurgeries in dogs. Veterinary Surgery, v.62, p.1-10, 2020. Available from: <Available from: https://pubmed.ncbi.nlm.nih.gov/32943076 >. Accessed: Jun. 20, 2021. doi: 10.1186/s13028-020-00545-z
https://pubmed.ncbi.nlm.nih.gov/32943076...
).The infection rate of 1.56% observed during our study was considered satisfactory and similar to those reported by other studies (DYALL & SCHMÖKEL, 2018VASSEUR, P. B. et al. Surgical wound infection rates in dogs and cats. Data from a teaching hospital. Veterinary Surgery, v.17, p.60-64, 1988. Available from: <Available from: https://www.ncbi.nlm.nih.gov/pubmed/3238876 >. Accessed: Jun. 08, 2020.
https://www.ncbi.nlm.nih.gov/pubmed/3238...
; VÄLKKI et al., 2020VÄLKKI, K. H. T. et al. Antimicrobial prophylaxis is considered sufficient to preserve an acceptable surgical site infection rate in clean orthopaedic and neurosurgeries in dogs. Veterinary Surgery, v.62, p.1-10, 2020. Available from: <Available from: https://pubmed.ncbi.nlm.nih.gov/32943076 >. Accessed: Jun. 20, 2021. doi: 10.1186/s13028-020-00545-z
https://pubmed.ncbi.nlm.nih.gov/32943076...
).

Suture dehiscence occurred in one dog (1.56%) without a concomitant superficial wound infection. Another dog (1.56%) experienced an adverse reaction to the surgical thread during the late postoperative period. LEXMAULOVÁ et al. (2008LEXMAULOVÁ, L. et al. Complications related to surgical treatment of intervertebral disc disease in dogs. Acta Veterinaria Brno, v.77, p.269-276, 2008. Available from: <Available from: https://actavet.vfu.cz/77/2/0269 >. Accessed: Feb. 15, 2020. doi: 10.2754/avb200877020269.
https://actavet.vfu.cz/77/2/0269...
) also evaluated the frequency of suture dehiscence in dogs that underwent spinal procedures and considered it to be low.

In one dog (1.56%), scarring occurred during the late postoperative period. Adherence affects skin mobility and, in humans, can often cause itchiness and discomfort (LI et al., 2021LI, S. et al. Autologous fat transplantation for the treatment of abdominal wall scar adhesions after cesarean section. Journal of Plastic Surgery and Hand Surgery, v.55, p.210-215, 2021. Available from: <Available from: https://pubmed.ncbi.nlm.nih.gov/33530846 >. Accessed: Dec. 15, 2021. doi: 10.1080/2000656X.2020.1856675.
https://pubmed.ncbi.nlm.nih.gov/33530846...
). However, such cases have not been reported in veterinary medicine. Notably, pain, discomfort, and itchiness were not observed during the late postoperative evaluation of the dogs.

Regarding the neurological outcomes, 76.56% (n = 49) experienced neurological improvement and 23.44% (n = 15) had grade V neurological dysfunction. One patient (1.56%) experienced worsening of the neurological status during the immediate postoperative period; however, it was transient. This deterioration probably occurred as a result of spinal cord manipulation during decompression that led to material adhering to the dura mater. Such complications have been reported by AIKAWA et al. (2012AIKAWA, T. et al. Long-term neurologic outcome of hemilaminectomy and disk fenestration for treatment of dogs with thoracolumbar intervertebral disk herniation: 831 cases (2000-2007). Journal of the American Veterinary Medical Association, v.241, p.1617-1626, 2012. Available from: <Available from: https://pubmed.ncbi.nlm.nih.gov/23216037/ >. Accessed: Jun. 20, 2020. doi: 10.2460/javma.241.12.1617.
https://pubmed.ncbi.nlm.nih.gov/23216037...
). Another study reported that 5% of dogs affected by IVDE experienced neurological deterioration attributable to the secondary effects of spinal cord compression and manipulation during hemilaminectomy (MARTIN et al., 2020MARTIN, S. et al. Same-day surgery may reduce the risk of losing pain perception in dogs with thoracolumbar disc extrusion. Journal of Small Animal Practice, v.61, p.442-448, 2020. Available from: <Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/jsap.13147 >. Accessed: Jan. 12, 2021. doi: 10.1111/jsap.13147.
https://onlinelibrary.wiley.com/doi/full...
); these findings were similar to those of our study.

This study was limited by the small number of included animals. Different frequencies of complications could be observed if larger samples are studied. Furthermore, evaluation times longer than 30 days could also reveal other complications or adverse effects.

Knowledge of complications associated with spinal cord decompressive surgery is important to the appropriate management of patients. Delicate manipulation of the spinal cord and nerve roots can prevent abdominal wall flaccidity or worsening of the neurological status. Smaller incisions that do not compromise access during surgery and allow the shortest possible surgical time, in addition to adherence to the principles of asepsis throughout surgery, may prevent infections and surgical wound dehiscence.

CONCLUSION:

Dogs that undergo surgical procedures of the spine to treat IVDE may experience complications during the intraoperative, immediate postoperative, and late postoperative periods. These complications are often transitory and rarely cause death. Some of these complications can be avoided. The surgical team is responsible for minimizing the frequency of complications and their consequent effects on patient recovery.

ACKNOWLEDGMENTS

This study was financially supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) process number 310969/2021-2 and was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brasil - Finance code 001.

REFERENCES

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  • CR-2022-0400.R1

ETHICS AND BIOSAFETY COMMITTEE

  • This research was approved by the regulatory institution after scientific, ethical and animal welfare consideration (CEUA 3512090617/UFSM).

Edited by

Felisbina Queiroga (0000-0001-6130-8381) Rudi Weiblen (0000-0002-1737-9817)

Publication Dates

  • Publication in this collection
    20 Mar 2023
  • Date of issue
    2023

History

  • Received
    14 July 2022
  • Accepted
    20 Dec 2022
  • Reviewed
    18 Mar 2022
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